Tmp_21700-Basic Science Summary for the MRCS-2069613412

1

BASIC SCIENCE

SUMMARY For the MRCS A summary of more than 1800 MCQs!

st

1 edition - 1434

By

Mahmoud Shoaib Neuro-surgery resident – resident – Tanta Tanta University [email protected] Drma7moud.blogspot.com 0114 14 955 76 – 76 – 0114 0114 610 16 16

Basic science summary for the MRCS

Mahmoud Shoaib

2

INDEX  ABBREVIATIONS ………………………………………………………… ... ………………………………… …………………………… …………………………… ……………… … .....  ANATOMY …………………… 1. Thorax …………………………………………………………………………………………………….. 2. Upper limb & breast ………………………………………………………………………………… ………………………………………………………………………………… 3. Lower limb ………………………………………………………………… ……………………………………………………………………………………………… …………………………….. 4. Head & neck …………………………………………………………………………………………… …………………………………………………………………………………………….. 5. Brain & cranial nerves ……………………………………………………………… ……………………………………………………………………………… ……………… 6. Back & spinal cord …………………………………………………………………………………… 7. Abdomen ……………………………………………………… ………………………………………………………………………………………………… ………………………………………… 8. Pelvis & perineum …………………………………………………………………………………… 9. Developmental anatomy …………………………………………………………………………. ………………………………………………………………………….

3 4 5 9 14 18 26 28 29 37 39



PHYSIOLOGY & PATHOLOGY ………………………………………… 42

1. 2. 3. 4. 5. 6. 7. 8. 9.

General physiology & blood …………………………………………………………………….. Fluids, electrolytes & acid-base balance – balance – renal system …………………………… CVS ………………………………………………………………………………………………………….. Respiratory system ………………………………………………………………………………….. GIT & hepato-biliary system ……………………………………………………………………. Neurology ……………………………………………………………………………………………… ……………………………………………………………………………………………….. .. Endocrinology ………………………………………………… …………………………………………………………………………………………. ………………………………………. Male re-productive system system ………………………………………………… ……………………………………………………………………… …………………… Female re-productive system & breast ………………………………………………… ……………………………………………………. ….

43 52 61 67 72 76 81 85 87



PATHOLOGY, MICRO-BIOLOGY & PHARMACOLOGY ……. ..

89

1. 1. 2. 3. 4. 5.

Cell injury & wound healing …………………………………………………………………….. Inflammation & immunology …………………………………………………………………… Neo-plasia ……………………………………………………………………………………………….. Site-specific Site-specific tumors ………………………………………………………… …………………………………………………………………………………. ………………………. Micro-biology Micro-biology ……………………………………………… ………………………………………………………………………………………….. ………………………………………….. Pharmacology …………………………………………………………… ………………………………………………………………………………………… ……………………………..

90 92 94 96 104 106



GENERAL COLLECTIONS ………………………………………………..

110

o

Tuberculosis & lymphatics ……………………………………………………………………… ………………………………………………………………………..

111


Mahmoud Shoaib

3

ABBREVIATIONS A ACE Angio-tensin Converting Enzyme. ASD Atrial Septal Defect.

ARF Acute Renal Failure.

B BP Blood Pressure. C CEA Carcino-Embryonic Antigen. CRF Chronic Renal Failure.

CO Cardiac Output. CVP Central Venous Pressure.

H HR Heart Rate. M MAP Mean Arterial Pressure.

N NK cell Natural Killer cell.

P PAWP Pulmonary Artery Wedge Pressure.

MRSA Methicillin-Resistant Staphylo-coccus Aureus.

NSGCTs Non-Seminomatous GermCell Tumors.

Pgs Prosta-glandins.

R RPF Renal Plasma Flow. S SLE Systemic Lupus Erythematosus. SVR Systemic Vascular Resistance. T TPA Tissue Plasminogen Activator.

SV Stroke Volume.

TPN Total Parenteral Nutrition.

U US Ultra-Sono-graphy. V VSD Ventricular Septal Defect.


Mahmoud Shoaib

4

ANATOMY


Mahmoud Shoaib

5

THORAX THORACIC CAGE 





th

The tubercle of the 7 rib articulates with the transverse process of T7. nd

Sternal angle is palpated to identify the 2 costal cartilage = T4-5 inter-vertebral disc = inferior border of superior mediastinum. st

The sterno-clavicular joint is in close proximity to the articulation of the 1 rib with the sternum.

The posterior inter-costal arteries: 1. The upper 2 arise from the supreme inter-costal artery, a branch of the costo-cervical trunk of the sub-clavian artery. 2. The lower 9 arise from the back of the thoracic aorta. 



1st aortic inter-costals supply the right bronchus.

The thoracic wall is innervated by the inter-costal nerves: 1) Ventral 1ry rami of spinal nerves T1-11 provide: 1. Motor innervation to inter-costal muscles & muscles of abdominal wall, fore-arm & hand. 2. Sensory innervation to the skin of the chest & abdomen on the anterior & lateral sides. 

2) Dorsal 1ry rami provide: 1. Motor innervation to true back muscles. 2. Sensory innervation to the skin on the back. 

Endo-thoracic fascia is a natural cleavage plane of CT for surgical separation of the costal parietal pleura from the thoracic wall.

THE LUNGS 







The carina is a keel-shaped cartilage at the tracheal bifurcation separating the right & left main stem bronchi. The oblique fissure of the right lung separates the lower lobe from the upper & middle lobes. The minor (horizontal) fissure separates the middle lobe from the upper lobe. A stab in the back nicking the left lung halfway between its apex & the diaphragmatic surface injures the inferior lobe as the posterior surface of the left lung is almost entirely composed of the inferior lobe.

Inhaled objects are more likely to enter the right lung (the right main bronchus) instead of the left lung. They are most likely to end in the superior segmental bronchus of the right lower lobe. Also, a right lung abscess is most likely to accumulate in the superior segment of the lower lobe.


Mahmoud Shoaib

6





1. 2. 3. 4. 5. 6. 7. 8.

Enlarged tracheo-bronchial LNs (at the tracheal bifurcation) irritate the left RLN. This nerve loops under the aorta to ascend to the larynx, lies immediately dorsal to the ductus arteriosus & may be injured during its ligation. A blood clot travelling from a leg vein to the apical segmental pulmonary artery passes through: IVC. Right atrium. Tricuspid valve. Right ventricle. Pulmonary trunk. Left pulmonary artery. Left superior lobar artery. Left apical segmental artery.

PLEURA 



The pulmonary ligament lies posteriorly inferior to the root of the lung. st

Cupola is the portion of the parietal pleura extending above the 1 rib. It lies superior to the upper edge of the left clavicle near its head.

In the erect posture, fluid tends to accumulate in the costo-diaphragmatic recess of the pleural space (the lowest extent of the pleural cavity) which is found at: 1. The mid-clavicular line between ribs 6 & 8. 2. The mid-axillary line between ribs 8 & 10. 3. The para-vertebral line between ribs 10 & 12. The aspiration needle is inserted in this recess at the top of the rib (or the bottom of the inter-costal space) for avoiding damage of the neuro-vascular bundle that is found below the rib, in the costal groove. 



1. 2. 3. 4. 



During aspiration of fluid from the pleural space, the structures passed through from superficial to deep are: External inter-costals. Internal inter-costals. Inner-most inter-costals. Parietal pleura. The costo-mediastinal recess is an area right next (just above) to the cardiac notch (an indentation in the superior lobe of the left lung only). During deep breath, the lingual which is formed by the cardiac notch expands into this recess.


Mahmoud Shoaib

7

DIAPHRAGM OPENINGS (VEA) Vena caval o o

o

o o

T8 In the central tendon & is quadrilateral in shape. 1" to the right of the mid-line. IVC. Right phrenic n.

Esophageal o o

o

o o

T10 In the right crus taking origin from L1-3. 1" to the left of the midline. Esophagus & its vessels. 2 vagi.

Aortic o o

o

o o o

T12 Behind the median arcuate ligament. In the mid-line.

Aorta. Azygos vein. Thoracic duct.

THE HEART 

The great cardiac vein is the largest tributary of the coronary sinus. It starts at the apex of the heart & ascends with the anterior ventricular bracnch of the left coronary artery.

The following cardiac veins do not end in the coronary sinus: 1. Anterior cardiac veins which collect blood from the right ventricle & open into the right atrium. 2. Smallest cardiac veins which arise in the muscular wall of the heart. 



A part of the right bundle branch of AV bundle is carried by the crsita terminalis.

Coronary arteries


Mahmoud Shoaib

8

Artery 1. Left coronary artery.

 

2. Circumflex branch of left coronary artery.



Supply Both ventricles. A part of the left branch of AV bundle. Left atrium & ventricle.

PERI-CARDIUM 



A hand slipped under the heart apex, passing upward & to the right within the sac & finally stopped by the cul-de-sac formed by the peri-cardial reflection near the heart base is in the oblique peri-cardial sinus. A finger passed immediately behind the 2 great arteries (pulmonary trunk & aorta) in the peri-cardial sac is inserted into the transverse per-cardial sinus.

MEDIASTINUM 













Mediastinal pleura form the lateral boundary of the superior mediastinum. The left brachio-cephalic vein courses across the mediastinum in a horizontal fashion. It lies immediately antero-superior to the ascending aorta & posterior to the thymus. The azygos vein lies in the posterior mediastinum & empties into the SVC. The esophagus lies posterior to the peri-cardial sac & may be compressed by a tumor of the posterior mediastinum. The thoracic duct extends from L2 to the root of the neck & lies immediately posterior to the esophagus & may be injured while mobilizing the esophagus in the neck. The ascending aorta lies in the middle mediastinum while the arch lies in the superior mediastinum leaving an impression on the mediastinal surface of the left lung. The left vagus nerve lies on & partly curves posteriorly around the arch of aorta.


Mahmoud Shoaib

9

UPPER LIMB & BREAST MUSCLES Muscle

Nerve supply

1. Pectoralis minor 2. Serratus anterior

3. Sub-scapularis: It is inserted into the lesser tuberosity of humerus. 4. Trapezius

Action 

Long thoracic n. (accompanied by long thoracic artery). o Upper & lower subscapular n1. o

o

Spinal accessory n. + C3-4.









Transverse cervical a. 

5. Latissimus dorsi: It forms the posterior wall of axilla.

6. Supra-spinatus: It is inserted into the uppermost facet of the greater tuberosity of humerus ( SIT). 7. Rhomboid major

Thoraco-dorsal (long sub-scapular) n. (C6, 7 & 8). It is accompanied by thoraco-dorsal a. from sub-clavian sub-clavian → axillary → sub-scapular. sub-scapular. o Supra-scapular n. (C56). o

o

Dorsal scapular n.

8. Pronator teres









9. Flexor carpi radialis

10.Extensor 10.Extensor carpi radialis brevis 11.Flexor 11.Flexor digitorum profundus



o

Depression of the glenoid fossa directly. Main protractor of scapula.

Paralysis



Winged scapula.

Adduction & medial rotation of humerus.

Upper fibers: elevation of the scapula. Middle fibers: retraction of the scapula. Lower fibers: rotation of the glenoid cavity upwards.





Inability to elevate the shoulder tip. Difficult full arm abduction.

Adduction, medial rotation & extension of humerus.

Initiation of abduction of humerus.

Retraction of scapula (antagonist to serratus anterior). Production of the main movement of the proximal radio-ulnar joint.

Abduction of the wrist.

Median & ulnar nerves.

1

The upper sub-scapular nerve is an infra-clavicular branch of the brachial plexus. The lower sub-scapular nerve supplies teres major.


Mahmoud Shoaib

10



1. 2. 3. 4. 



  

Shoulder stabilizers (rotator cuff): "SITS" Supra-spinatus. Infra-spinatus. Teres minor. Sub-scapularis. All anterior compartment muscles of the arm are supplied by the musculo-cutaneous nerve. All superficial fore-arm muscles originate from the common flexor origin (the front of the medial epi-condyle). So, a displaced fracture of the medial epi-condyle affects all these muscles but not the deep muscles. All adductors of the digits (palmar inter-ossei) are supplied by the ulnar nerve (C 8 & T1). All hypo-thenar muscles are supplied by the ulnar nerve (C 8). The lumbrical muscles assist in extension of the middle & distal phalanges.

ARTERIES Branches of the axillary artery: st 1. 1 part: superior thoracic artery. nd 2. 2 part: acromio- thoracic & lateral thoracic arteries. rd 3. 3 part: sub-scapular artery (the largest branch) - Posterior & anterior circumflex humeral arteries. 



Arteria princeps pollicis supplying the thumb is a branch of the radial artery.

NERVES Nerve 1. Median nerve

Injury 



2. The roots of C5-6



3. Musculo-cutaneous nerve





4. Radial nerve: It spirals around the humerus in the radial groove & may be injured in fractures of the middle of the humerus. 5. Posterior inter-osseus nerve






Atrophy of the thenar eminence (flexor & abductor pollicis brevis & opponens pollicis). Numbness of skin over it. Loss of abduction of the arm (Erb Duchenne's paralysis). Weakness of shoulder & elbow flexion & arm supination. Loss of cutaneous sensation on the t he antero-lateral surface of the fore-arm. Numbness on the dorsum of the thumb & parts of digits 1 & 2.

Inability to extend the wrist & metacarpo-phalangeal joints.

Mahmoud Shoaib

11

MISCELLANEOUS Site of axillary LNs: 1. Apical are medial to the medial edge of the pectoralis minor muscle. 2. Central are behind the muscle (draining 75% of the breast lymph). 3. Lateral, pectoral & sub-scapular are lateral to the medial edge of the muscle. 

The quadrangular space of the shoulder contains: 1. Axillary nerve. rd 2. Posterior circumflex humeral artery (a branch of 3 part of axillary artery & is injured in fracture of the surgical neck of humerus). 













The inter-tubercular (bicipital) groove of the humerus contains the tendon of the long head of biceps brachii muscle. Elbow joint is of the hinge type. A fracture passing through the superior surface of olecranon process of ulna disrupts the attachment of triceps brachii. Olecranon process is used for resting elbows on the desk.

Annular ligament encircles the head of radius & its injury makes supination painful. The extensor retinaculum prevents the tendons of the posterior compartment of the forearm from "brow-stringing" when when the hand is extended. The anatomical snuffbox contains the radial artery.

Brachial plexus


Mahmoud Shoaib

12

Anastomosis Anastomosis around around elbow joint Radial recurrent artery lies on supinator muscle, immediately below the elbow.

Carpal bones

From lateral to medial: 1 2 1. Proximal row: Scaphoid – caphoid – Lunate – Triquetrum – riquetrum – Pisi-form . 2. Distal row: Trapezium – rapezium – Trapezoid – rapezoid – Capitate – apitate – Hamate. 

!

1 2

..

It is most commonly dis-located by a fall on the out-stretched hand. It has a single articular facet.


Mahmoud Shoaib

13

Dermatomes of the upper limb


Mahmoud Shoaib

14

LOWER LIMB MUSCLES Muscle

Nerve supply

1. Gluteus maximus

o

2. Gluteus medius

o

Inferior gluteal nerve (L5 & S1-2). Superior gluteal nerve (L4-5 & S1).

3. Sartorius

o

4. Quadriceps femoris: It is inserted into tibial tuberosity. 5. Pectineus 6. Biceps femoris: Its long head crosses 2 joints.

7. Semi-tendinosus 8. Semi-membranosus

Femoral nerve (dorsal divisions of L2, 3 & 4).

1. Tibial nerve (long head). 2. Common peroneal nerve (short head).

Action 1. 2. 1. 2.

Main extensor of the hip. Lateral rotation of the thigh. Abduction of the hip. Medial rotation of the thigh.  It acts on 2 joints putting the lower limb in cross-leg position: 1. Flexion, abduction & lateral rotation of the thigh. 2. Flexion & medial rotation of the leg. Extension of the leg. 







o

Sciatic nerve. 

 

  

Extension of the hip & flexion of the knee. Lateral rotation of the leg.

Extension of the hip & flexion of the knee. Medial rotation of the leg.

Obturator internus muscle emerges from the pelvis through the lesser sciatic foramen. Adductors of the thigh (longus, brevis & pubic part of magnus) are inserted into linea aspera of the femur. All superficial muscles of the back of the leg are inserted into the calcaneus. Peroneus brevis muscle is inserted into the base of the 5 th meta-tarsal bone. Tibialis posterior is inserted into the tuberosity on the medial surface of navicular.

ARTERIES & VEINS 

Obturator artery is found in the medial compartment of the thigh. It gives the artery of the round ligament of the head of femur.

Femoral artery → popliteal artery → 1. Posterior tibial artery → peroneal artery (between artery (between Tibialis posterior & flexor Hallucis longus). 2. Anterior tibial artery → dorsalis pedis artery → deep plantar artery – artery – medial medial & lateral tarsal arteries. 



The popliteal artery is crossed in its middle part from lateral to medial by the tibial nerve & the popliteal vein.


Mahmoud Shoaib

15

Arteries supplying the hip joint: 1. Obturator & femoral arteries. 2. Medial & lateral femoral circumflex arteries (injury of the medial artery after fracture of the femoral neck causes avascular necrosis of the head). 3. Superior & inferior gluteal arteries. 



Superficial external pudendal artery passes through the saphenous opening.

Profunda femoris (deep femoral) artery gives: 1. Medial & lateral circumflex femoral arteries. 2. 4 perforating branches which supply the posterior compartment of the thigh. 



Great saphenous vein terminates in the femoral vein within the femoral sheath.

The small saphenous vein begins posterior to the lateral malleolus as as continuation of the lateral marginal vein (dorsal venous arch), has 9-12 valves & is in close relation with: 1. Sural nerve in the lower 1/3 of the leg. 2. Medial sural cutaneous nerve in the upper 2/3 of the leg. It terminates in the popliteal vein. 



The pulsation of dorsalis pedis artery is felt just lateral to the tendon of extensor hallucis longus.

NERVES 



Obturator nerve (ventral divisions of L2, 3 & 4) emerges from the medial border of psoas major muscle & passes through the obturator foramen. It innervates the medial compartment of the thigh (adductors). The lateral femoral cutaneous nerve arises from the dorsal divisions of L2-3.

Sciatic nerve gives: 1. Medial popliteal (tibial) nerve: It supplies superficial muscles of back of leg (gastrocnemius, plantaris & soleus) & popliteus. st It gives medial (flexor digitorum & hallucis brevis, abductor hallucis & 1 lumbrical) & lateral plantar nerves (other muscles in the sole of the foot). It ends by becoming posterior tibial nerve which supplies deep muscles of back of leg except popliteus "Tom Does Homework" (Tibialis posterior, flexor Digitorum longus & 1 flexor Hallucis longus ). 

2. Lateral popliteal (common peroneal) nerve gives: 1) Superficial peroneal (musculo-cutaneous) nerve which supplies muscles o f the lateral aspect of the leg (peroneus longus & brevis) & skin on the dorsum of the foot. 2) Deep peroneal (anterior tibial) nerve (L4-5 & S1) which supplies "Tom Has Dog Pobby" (Tibialis anterior, extensor Hallucis longus, extensor Digitorum longus, Peroneus tertius) & extensor digitorum brevis It is injured in fracture of the upper end of fibula. 1

Its function is affected in a fracture of the sustentaculum tali.


Mahmoud Shoaib

16

MISCELLANEOUS 



1. 2. 3. 4. 

Ischial tuberosities are used for sitting on. Boundaries of the femoral triangle: Laterally: the medial border of Sartorius. Medially: the lateral border of adductor longus. Base (above): the inguinal ligament. Apex (below): meeting of Sartorius & adductor longus. It is continuous below with the adductor canal.

The femoral sheath is divided into 3 compartments: 1. The medial is called the femoral canal. 2. The middle contains the femoral vein. 3. The lateral contains the femoral artery. 



The femoral nerve lies lateral to the femoral artery (outside the femoral sheath).

Sub-sartorial (Hunter's or adductor) canal contains: 1. Femoral artery & vein. 2. Saphenous nerve. 3. Nerve to vastus medialis. 

1. 2. 3. 4.

Popliteal fossa is bounded by: Supero-laterally: Biceps femoris. Supero-medially: Semi-tendinosus & semi-membranosus. Infero-laterally: Medial head of gastrocnemius. Supero-laterally: Lateral head of gastrocnemius & plantaris.



Tibial nerve is the most superficial structure encountered in the popliteal fossa.



1. 2. 3. 4.

Structures on the lateral aspect of the knee from superficial-to-deep: Skin. Fibular collateral ligament. Popliteus muscle tendon. Lateral meniscus.



The knee joint consists of 3 articulations in one.



 





The anterior cruciate ligament damage causes "anterior drawer sign". The posterior cruciate ligament prevents posterior sliding of the tibia on the femur. st

The 1 ligament to rupture with a plantar-flexion-inversion ankle sprain is the anterior talo-fibular ligament which is the shortest of the 3 lateral ankle ligaments.

Twisting of the ankle with forcible eversion during skiing will most probably strain the deltoid ligament.


Mahmoud Shoaib

17

Bones of the foot

Dermatomes of the upper limb


Mahmoud Shoaib

18

HEAD & NECK Cranial fossa Anterior

Skull foramina & contents Foramina st 1.Cribri-form 1.Cribri-form plate  1 CN.  Emissary veins.

2.Optic 2.Optic canal

 

Ophthalmic veins.



Sympathetic nerves.



Maxillary division division of tri-geminal nerve.



Middle



4.F. 4. F. rotundum 5.F. 5. F. ovale

 

6.F. 6. F. spinosum

 

7.F. 7. F. lacerum



8.F. 8.F. magnum



 

9.Jugular 9.Jugular F.

 

Posterior



10. Hypo-glossal canal

 

11. Internal auditory (acoustic) meatus

nd

2 CN. Ophthalmic artery. rd th th 3 , 4 & 6 CNs. Ophthalmic division of tri-geminal nerve.



3.Superior 3.Superior orbital fissure

Contents

 

Mandibular division division of tri-geminal nerve. Accessory meningeal artery.

Middle meningeal artery. Meningeal branch of mandibular nerve. ICA. Medulla oblongata, continuing into spinal cord & dura matter. Vertebral arteries. Accessory nerves. th th th 9 , 10 & 11 CNs. IJV (continuation of sigmoid sinus). Inferior petrosal sinus. th 12 CN. Meningeal branch of ascending pharyngeal artery. 7th & 8th CNs1. Labyrinthine artery.

BONE 





1

The pterion is an important clinical landmark because it overlies the anterior branches of the middle meningeal artery. It marks the junction between 3 bones: sphenoid, parietal & temporal. A blow to the pterion (as in boxing) may rupture the artery causing an extra-dural (epidural) hematoma between the dura & the cranial bone. The sphenoid bone contains the optic foramen, superior orbital fissure, foramen rotundum, ovale & spinosum. The medial boundary of the infra-temporal fossa is formed by the lateral pterygoid plate of the sphenoid bone.

th

So, an acoustic neuroma (tumor of the 8 CN) is also likely to involve the facial nerve.


Mahmoud Shoaib

19



The mental foramen is found in the mandible.



Styloid process of the temporal bone cannot be easily palpated in a live subject.





The pterygo-mandibular raphe serves as an attachment for the superior pharyngeal constrictor muscle. The hyoid bone serves as an attachment for the middle pharyngeal constrictor muscle.

MUSCLES 

The rectus capitis anterior muscle is innervated by ventral rami from C1-2.

Both tensors are supplied by the mandibular division of the tri-geminal nerve: 1. Tensor veli palate that opens the auditory tube & tenses the palate. It hooks around the pterygoid hamulus of the medial pterygoid plate. 2. Tensor tympani that tenses the tympanic membrane (supplied by the otic ganglion). 



The otic ganglion is found on the medial side of the mandibular division of the trigeminal nerve. th It receives its pre-ganglionic sympathetic fibers from the 9 CN (glosso-pharyngeal).



The stapedius dampens the movement of the stapes & is supplied by the facial nerve.



The muscles of facial expression are in the same sub-cutaneous plane as the platysma.

The lateral pterygoid muscles: 1. Acting alone, they shift the mandible to the opposite side. 2. Acting together, they protrude the mandible. 





1. 2. 3. 4.

The palato-glossus muscle is contained in the anterior palatal arch. th It acts on the tongue & is supplied (with the levator veli palatini) by the 10 CN (vagus) via the pharyngeal plexus. Muscles of the vocal folds (innervated by the recurrent laryngeal nerve): Crico-thyroid Tensor (the only muscle i nnervated by the o external branch of the superior laryngeal). Thyro-arytenoid. Relaxer. o Posterior crico-arytenoid Abductor. o Arytenoid, lateral crico-arytenoid Adductors. o & thyro-arytenoid

ARTERIES 



The internal carotid artery passes through the carotid canal in the petrous part of the temporal bone to reach the intra-cranial cavity. The anterior cerebral artery supplies the medial surface of the frontal, parietal & limbic lobes.


Mahmoud Shoaib

20





o

o

o

o

st

The middle meningeal artery is a branch of the 1 (retro-mandibular) part of the maxillary artery & is the principal artery supplying the meninges. Branches of the external carotid artery: Anterior branches: 1. Superior thyroid artery. 2. Lingual artery: To reach it from inside the mouth, you should go through the hyo-glossus muscle. 3. Facial artery: It is crossed by the branches of the facial nerve from behind forward. It can be felt pulsating at the lower border of the mandible just anterior to the masseter muscle which consists of superficial & deep portions. Its ligation here will ↓ blood flow to some parts of the nasal septum (through superior labial artery which gives a septal branch). Posterior branches: th 4. Occipital artery (it is associated laterally with the 12 CN (hypo-glossal)). 5. Posterior auricular artery. Ascending branch: 6. Ascending pharyngeal artery. Terminal branches: 7. Superficial temporal artery (its pulsation is felt in front of the upper part of the ear ). 8. Internal maxillary artery. ECA may be damaged during surgery of the parotid.





1. 2. 3. 4.

The central artery of the retina is the 1 st & one of the smallest branches of the ophthalmic artery. It is the sole supply for the retina. Branches of the lingual artery: Hyoid branch supplying the muscles attaches to the hyoid bone. Dorsal lingual artery on the superficial posterior surface of the tongue. Deep lingual artery (profunda linguae) on the deep surface of the tongue. Sub-lingual artery in the floor of the mouth supplying the sub-lingual gland. th

It is crossed by the 12 CN (hypo-glossal). rd

Branches of the 3 part of the internal maxillary artery: 1. Spheno-palatine artery (artery of epistaxis) which supplies the lateral nasal wall & nasal septum. 2. Descending palatine artery which arises within the pterygo-palatine fossa. 

Branches of the thyro-cervical trunk: st 1. Inferior thyroid artery which passes medially o ver the 1 portion of the vertebral artery. 2. Transverse cervical artery. 3. Supra-scapular artery which passes over the phrenic nerve (C3, 4 & 5) to enter the posterior triangle of the neck. 


Mahmoud Shoaib

21

VEINS & SINUSES 



The dural venous sinuses are located between the 2 layers (meningeal & periosteal) of the dura matter. Infections in the skin of the face, scalp or diploic bone of the neuro-cranium reach the dural venous sinuses because valves do not exist in the veins of these areas & they communicate directly with the dural venous sinuses through the superior ophthalmic vein.



An infected blood clot courses through the facial vein to the cavernous sinus. The cavernous & transverse sinuses are connected by the superior petrosal sinus.



The pterygoid venous plexus drains the infra-temporal fossa via the maxillary vein.



NERVES Nerve supply of the lacrimal gland : 1. General sensation is supplied by the ophthalmic nerve. 2. Para-sympathetic supply originates from the lacrimal nucleus of the facial nerve in the pons & travels via the pterygo-palatine ganglion & maxillary nerve. It can be injured by compression at the internal acoustic meatus resulting in dry eye. 3. Post-ganglionic sympathetic fibers originate from the superior cervical ganglion & travel through the same route as the para-sympathetic fibers. 

Autonomic nerve supply of the muscles of the iris: 1. Post-ganglionic sympathetic fibers originate from the superior cervical ganglion & innervate the dilator pupillae muscle. 2. Post-ganglionic para-sympathetic fibers originate from the ciliary ganglion & innervate rd the sphincter pupillae muscle (3 CN (oculo-motor)). 

The ciliary ganglion would be affected by severance of the 3rd CN. rd

The 3 CN (oculo-motor) supplies: 1. The levator palpebrae superioris which elevates the upper eyelid. 2. The sphincter pupillae muscles. 

Its damages causes eyelid drooping & dilated pupil. 







Injury to the sympathetic efferent fibers of the oculo-motor nerve will affect the ciliary muscle. The cell bodies of the para-sympathetic pre-ganglionic nerve fibers to the ciliary muscle rd of accommodation are located in the 3 CN nucleus (Edinger-Westphal nucleus).

Motor innervation of the orbicularis oculi muscle is by a branch of a nerve that exists through the stylo-mastoid foramen. Damage to the facial nerve after it emerges from the stylo-mastoid foramen would affect facial expression.


Mahmoud Shoaib

22









The ophthalmic division of the tri-geminal nerve as a single structure does not reach the interior of the globe. It carries general sensory innervation of the cornea. The supra-trochlear nerve is the terminal branch of the frontal nerve which is the largest branch of the ophthalmic nerve & is situated on the superior surface of the levator palpebrae superioris. The inferior palpebral nerve is the terminal branch of the infra-orbital branch of the maxillary nerve. Pre-ganglionic para-sympathetic fibers to the nose synapse in the pterygo-palatine ganglion.

The vidian nerve running in the pterygoid canal contains: 1. Post-ganglionic sympathetic fibers (deep petrosal nerve). 2. Pre-ganglionic para-sympathetic fibers (great petrosal nerve). 



o

o



o

o





Nerve supply of the tympanic membrane: Outer surface: 1  Upper & anterior part: auriculo-temporal branch of the mandibular nerve . th  Lower & posterior part: auricular branch of 10 CN (vagus). Inner surface: th  Tympanic branch of 12 CN (glosso-pharyngeal). Nerve supply of the tongue: Sensory:  Anterior 2/3: lingual nerve (general sensation) & chorda tympani (taste, also though the lingual nerve).  Posterior 1/3: glosso-pharyngeal nerve (all sensations). Motor: th  Hypo-glossal nerve (all muscles except palate-glossus which is supplied by the 10 CN (vagus)). Chorda tympani can be injured by erroneous placement of a tympanic membrane shunt as it runs across the ear-drum.

The inferior alveolar nerve is the largest branch of the mandibular nerve. It supplies sensory innervation to the mandibular teeth & bone.

Laryngeal nerves: 1. Superior laryngeal nerve which gives:  External laryngeal nerve: It may be injured in thyroid surgery during ligation of the superior thyroid artery. 



Internal laryngeal nerve: It supplies the mucosa of the larynx superior to the true vocal folds.

1

Its injury results in loss of sensation from the temporal region & loss of secretory secretory function of the parotid gland.


Mahmoud Shoaib

23

2. Recurrent laryngeal nerve:  It runs along the posterior surface of the thyroid gland. t he true vocal folds.  It supplies the mucosa of the larynx inferior to the  Its injury causes hoarseness of voice.  Its inferior laryngeal branch supplies the posterior crico-arytenoid muscle. 







The transverse cervical nerve (C2-3) carries touch sensation from the skin of the anterior triangle of the neck. The ansa cervicalis is embedded in the carotid sheath & is therefore vulnerable to injury during surgical procedures to the carotid artery. The phrenic nerves course over anterior scalene muscles in the neck. It is accompanied by the peri-cardio-phrenic branch of the internal mammary artery in the thorax. The supra-clavicular nerve may be injured with a stab in the posterior triangle of the neck 4 cm above the clavicle causing anesthesia over the acromion & clavicle.

THYROID, SUB-MANDIBULAR & PAROTID GLANDS 

1. 2. 3. 4. 5.

During thyroidectomy, the order of structures encountered, from superficial to deep is: Skin. Investing fascia. Pre-tracheal fascia. Thyroid gland. Para-thyroid glands.

Arterial supply of the thyroid gland: 1. Superior thyroid artery from external carotid artery. 2. Inferior thyroid artery from thyro-cervical trunk of sub-clavian artery. 3. The thyroidea ima artery which would take origin from the: 1) Brachio-cephalic trunk (innominate artery). 2) Aorta. 3) Right carotid artery, sub-clavian or internal mammary. 

Venous drainage of the thyroid gland: 1. Superior thyroid vein to IJV. 2. Middle thyroid vein to IJV. 3. Inferior thyroid vein from the isthmus to brachio-cephalic vein (left innominate vein). 





The parotid duct reaches the oral vestibule by piercing the buccinators muscle. The sub-mandibular duct opens near the mid-line in the anterior aspect of the floor of the mouth beside the lingual frenulum through the sub-lingual caruncle.


Mahmoud Shoaib

24

THE EYE 

Aqueous humor is the only source of nutrients for the lens of the eye.



The anterior chamber of the eye is separated from the posterior chamber by the iris.



Directing the gaze downward when the eye is abducted requires the IR muscle.



To test the 4 CN (trochlear), have the patient gaze in (medially), then down.

th

MISCELLANEOUS 

The nerves & blood vessels to the scalp are found in the CT layer.

The deep cervical fascia (fascia colli = investing fascia) invests: 1. The carotid vessels. 2. The muscles forming the borders of the posterior triangle of the neck. 



Infection in the mastoid air cells could probably be transmitted to the middle ear directly through the epi-tympanic (attic) recess. It could result from entry of bacteria through the naso-pharyngeal tube.



The vocal ligaments are formed by the superior free edge of the conus elasticus.



The pyri-form recess is located on either side of the larynx within the laryngo-pharynx. laryngo-pharynx.





The inferior part of the carotid sheath contains: common carotid artery, internal th jugular vein & 10 CN (vagus). The sympathetic trunk lies parallel & immediately deep to the carotid sheath in the neck.

The carotid body is located behind the angle of bifurcation of the common carotid artery (C4 = the upper border of thyroid cartilage). th It is supplied by the 9 CN (glosso-pharyngeal) & senses changes in blood composition (it detects ↓ PaO 2 "dissolved O 2 only") by chemo-receptors.

Sinus 1. Sphenoidal sinus. 2. Frontal & maxillary sinuses. 3. Naso-lacrimal duct.

  


Meatus Superior meatus. Middle meatus. Inferior meatus.

Mahmoud Shoaib

25

Triangles of the neck


Mahmoud Shoaib

26

BRAIN & CRANIAL NERVES ARTERIES & VEINS 







Cerebral artery thrombosis causes contra-lateral hemi-plegia. Occlusion of the posterior inferior cerebellar artery is most likely to affect the entire dorso-lateral part of the rostral medulla & produce the lateral medullary syndrome.

The superior cerebral veins (8-12) drain into the superior sagittal sinus. The great cerebral vein (of Galen) is formed by the union of the 2 internal cerebral veins.

CRANIAL NERVES 

th

Lesions of the 9 CN (glosso-pharyngeal) would result in general sensory deficit to the pharynx.



11th CN (abducens) is purely motor.



12 CN (hypo-glossal) supplies the hyo-glossus muscle.

th

MISCELLANEOUS 

A lesion (stroke) of the optic radiation causes homonymous hemianopia.



Cerebral aque-duct is located between the 3rd & 4th ventricles.

1. 2. 3. 4.

Tumor site The choroidal plexus of the lateral ventricle. The roof of the posterior horn of the LV. The medial wall of the body of the LV. The floor of the inferior horn of the LV. th

5. The floor of the 4 ventricle.



  




Compressed structure The caudate nucleus. Fibers of the corpus callosum. Posterior part of the septum pellucidum. Inferior surface of the tapetum of the corpus callosum. Abducent nerve nucleus.

Mahmoud Shoaib

27

Cerebral arterial circle (of Willis) It is contained in the cisterna basalis


Mahmoud Shoaib

28

BACK & SPINAL CORD BONE 

The vertebrae in the upper 3 regions of the column are true (movable) while those in the lower 2 regions are false (fixed).

A typical vertebra consists of: 1. An anterior segment (body) which has a few small apertures for the passage of nutrient vessels on its anterior surface in thoracic vertebrae. 2. A posterior segment (vertebral or neural arch) which consists of a pair of pedicles & a pair of laminae. 



The spinous process serves for the attachment of muscles & ligaments.



The 7 cervical vertebra has a F. transversarium for the passage of the vertebral artery.



th

Iliac crests are palpated to identify the spine of L4 for performing a lumbar puncture. Immediately superior to the iliac crest, the hernia passes through the lumbar triangle.

NERVES 







A lesion in the caudal medulla affecting the spinal tri-geminal tract will result in ipsilateral loss of perception of pain over much of the face. ry

The cutaneous branch of the posterior 1 ramus of C2 is the greater occipital nerve. Itching sensation from the skin immediately over the base of the spine of scapula is ry mediated through the posterior 1 ramus of C7.

Absent vibration sense in toes indicates a lesion in the posterior white columns of SC.

MISCELLANEOUS 









The spinal arachnoid matter is thinner than the cranial part & invests the cauda equina. The sub-arachnoid cavity communicates with the general ventricular cavity of the brain by 3 openings. It is very wide in the spinal part. The ligamentum denticulatum separates the anterior from the posterior nerve roots. The medial group of nuclei in the anterior a nterior horn of the spinal cord controls the function of the axial muscles. Affection of substantia gelatinosa (a nucleus of the posterior grey column) results in loss of pain & temperature sensations.


Mahmoud Shoaib

29

ABDOMEN PERITONEUM & LIGAMENTS 

The inguinal ligament is formed by the external abdominal oblique aponeurosis.



The cremasteric muscle is an extension of the internal abdominal oblique muscle.



Suspensory muscle of duodenum (ligament of Treitz) suspends the duodeno-jejunal flexure to the right crus of diaphragm.

Splenic ligaments: 1. Gastro-splenic ligament (between stomach & splenic hilum) contains left gastro-epiploic & short gastric vessels. 2. Lieno (spleno)-renal ligament (between left kidney & splenic hilum) contains splenic vessels & tail of pancreas. 



Pancreas is normally the least mobile structure in the peritoneal cavity.

1. 2. 3. 4. 5.

The following structures are retro-peritoneal: Part of esophagus & rectum. nd rd th 2 , 3 & 4 parts of duodenum. Pancreas. Kidneys, supra-renal glands, bladder & ureters. IVC.



The spleen is completely covered by peritoneum.



INGUINAL CANAL & HERNIA 

Pubic tubercle is felt down the edge of the medial crus of the superficial inguinal ring deep to the lateral edge of the spermatic cord.

1. The superficial inguinal ring is an opening in the external abdominal oblique aponeurosis. 2. The deep inguinal ring is above the mid-point of the inguinal ligament. of the inguinal canal is formed by the arched fibers of internal oblique & 3. The roof of transversus abdominis. 





The round ligament of the uterus passes through the deep inguinal ring & then alongside the indirect inguinal herniated mass in the inguinal canal. A lump protruding from the superficial inguinal ring is either a direct or an indirect inguinal hernia. A left-sided indirect inguinal hernia most likely involves the sigmoid colon as it is mobile due to the presence of sigmoid meso-colon.


Mahmoud Shoaib

30

GASTRO-INTESTINAL TRACT nd

The 2 (descending) part of the duodenum: 1. The major duodenal papilla is located at the middle of the postero-medial aspect of it. 2. The right colic flexure lies anterior to it. 3. The hilum of the right kidney may be injured while mobilizing this part. 









rd

Nutcracker-like compression of the 3 (transverse) part of the duodenum occurs between the superior mesenteric artery & the aorta.

Distal jejunum, caecum & vermi-form appendix lie within the right lower quadrant of the abdomen. On a barium contrast X-ray, the small intestine is characterized by circular folds of the mucosa. During appendicectomy, the appendix is located by looking at the confluence of taenia coli.

During exploratory laparotomy: 1. The jejunum is characterized by sparse aggregated LNs & larger villi. 2. The ileum is characterized by larger & more numerous aggregated LNs. 3. The large intestine is characterized by epi-ploic appendages. 



The rectum is an important anastomosis site for the portal & caval (systemic) venous systems.

SPLEEN, LIVER & PANCREAS The spleen is injured in case of: th th 1. Fractures near the angles of the left 9 & 10 ribs. c olic flexure. 2. Traction on the attachment between the spleen & the left colic 









The division between the true (functional or internal) right & left lobes of the liver may be visualized on the outside as a plane passing through the gall-bladder fossa & IVC. th

th

The superior liver surface is related to the 7 & 8 costal cartilages on the left side. During laparo-scopic chole-cystectomy, cystic artery is exposed in the triangle of Calot between common hepatic dust, liver & cystic duct. th

The fundus of the gall-bladder usually lies at the tip of the 9 costal cartilage in the mid-clavicular line.



The common bile duct lies behind the head of pancreas, close to the right border.



The main pancreatic duct is also called the duct of Wirsung.


Mahmoud Shoaib

31

BLOOD VESSELS

Arterial supply supply of the the stomach stomach

Superior & inferior mesenteric arteries


Mahmoud Shoaib

32

Renal, supra-renal & gonadal veins

Arterial supply of the esophagus: 1. The thyro-cervical trunk. 2. The left inferior phrenic artery. 3. The left gastric artery. 

Arterial supply of supra-renal glands: 1. Superior supra-renal from inferior phrenic artery. 2. Middle supra-renal from abdominal aorta. 3. Inferior supra-renal from renal artery. 











The splenic artery gives off short gastric arteries which supply blood to the fundus of the stomach.

The hepatic artery passes near the upper margin of the superior part of the duodenum & also forms the lower boundary of the epi-ploic foramen (foramen of Winslow). The hepatic veins are arranged in 2 groups. The superior mesenteric artery courses between the body & uncinate process of the pancreas before it supplies the jejunum & ileum. It lies immediately posterior to the neck of pancreas. It gives the inferior pancreatico-duodenal artery supplying the pancreas. The IVC if formed by the junction of the 2 common iliac veins on the right side of L5.


Mahmoud Shoaib

33















The inferior epi-gastric artery is a branch of the external iliac artery near the deep inguinal ring. It runs in the extra-peritoneal CT (pre-peritoneal fat, between transversus abdominis muscle & peritoneum) vertically just medial to the bowel as the bowel passes through the abdominal wall. It will have increased flow through it after dividing the internal thoracic artery at its distal end so that adequate blood flow is maintained to the rectus abdominis on the left site. Inferior mesenteric artery occlusion is seldom (rarely) symptomatic because its territory may be supplied by branches of left & middle colic arteries. Inferior mesenteric vein does not run a course parallel to superior mesenteric artery however they supply/drain the same region. The marginal artery is the anastomotic artery running along the border of the large intestine. The artery of Adamkiewicz is a radicular artery on the left side in the lower thoracic or upper lumbar region. The middle sacral artery is a branch of the abdominal aorta. The superior gluteal artery exists the pelvis between the lumbo-sacral trunk & S1 nerve.

NERVES & PAIN Blood & para-sympathetic supply of the abdominal organs: 1. All GIT up to the last Vagus nerve. o Celiac trunk & superior part of the transverse Its compression may mesenteric artery colon: result in a loss of (artery of the mid-gut elevation of the soft around which the mid palate. gut bends). 2. All GIT distal to that Pelvic splanchnic nerves. o Inferior mesenteric point. artery. 







The celiac ganglia are traversed by vagal (para-sympathetic) fibers that do not synapse in the ganglia.



Liver, duodenum & gall-bladder pain radiates to the right shoulder & scapula. Myo-cardial infarction pain is referred to the left upper extremity by the left intercosto-brachial nerve.



A spinal cord injury at T10 results in loss of cutaneous sensation from umbilicus to toes.







Injury of the ilio-hypo-gastric nerve (L1) during appendicectomy results in paraesthesia (numbness) of the skin at the pubic region (lower abdominal wall), upper hip & thigh.

The ilio-inguinal nerve passes through the superficial inguinal ring.


Mahmoud Shoaib

34

Its injury during appendicectomy results in weakness of the falx inguinalis resulting in a right direct inguinal hernia. It is compressed by a long-standing large indirect inguinal hernia producing pain in the scrotum. Its terminal branch is the anterior labial (scrotal) nerve which supplies the skin of the mons pubis.

INCISIONS 





st

An incision in the epi-gastric region is used to treat an ulcer in the 1 part of the duodenum. During a transverse supra-pubic (Pfannenstiel) incision, posterior rectus sheath will not be encountered as it ends in a thin curved margin (arcuate line or linea semicircularis) half-way between umbilicus & symphysis pubis. A mid-line incision between the 2 rectus sheaths passes through the linea alba.

MISCELLANEOUS 

The trans-pyloric plane lies roughly a hand's breadth below the xephi-sternal junction.

The venous & lymphatic drainage of the superficial tissue of the anterior abdominal wall is arranged around a horizontal plane corresponding to the level of the umbilicus: 1. Above that plane, drainage is in a cranial direction (axillary LNs & superior epi-gastric vein → internal thoracic vein). 2. Below the plane, drainage is in a caudal direction (superficial inguinal LNs & inferior epi-gastric epi-gastric vein → external iliac vein). vein ). 



A bypass between the vessels between the portal & caval systems for treating portal hypertension can be done between splenic vein (portal) & left renal vein (caval).

The anterior relations of the supra-renal gland include: 1. On the right side: IVC. 2. On the left side: pancreas. 





The un-descended testis is least likely to be found in the perineum. The site of the cloacal membrane (the point of demarcation between the endo-dermal & ecto-dermal epithelium "upper 2/3 & lower 1/3") is represented in the adult anal canal by the anal valves (pectinate/dentate line).


Mahmoud Shoaib

35

Epi-ploic foramen (foramen of Winslow)


Mahmoud Shoaib

36

The lower anterior abdominal wall as seen from inside the peritoneal cavity (top) & in the transverse plane (bottom)

36

The lower anterior abdominal wall as seen from inside the peritoneal cavity (top) & in the transverse plane (bottom)


Mahmoud Shoaib

37

PELVIS & PERINEUM GENITAL TRACT 

The fallopian tubes lie between the 2 layers of the meso-salpinx.



The base of the prostate is directly related to the urinary bladder.

The seminal vesicles are found between the base of the bladder & rectum. The arteries supplying them are derived from: 1. Middle & inferior vesical arteries. 2. Middle rectal arteries. 





The ductus deferens unites with the duct of the seminal vesicle to form the ejaculatory duct which perforates the prostate gland to open into the prostatic urethra. An extensive malignant growth in the anterior wall of the vagina is most likely to involve the fundus of the bladder.

BLOOD VESSELS

37

PELVIS & PERINEUM GENITAL TRACT 

The fallopian tubes lie between the 2 layers of the meso-salpinx.



The base of the prostate is directly related to the urinary bladder.

The seminal vesicles are found between the base of the bladder & rectum. The arteries supplying them are derived from: 1. Middle & inferior vesical arteries. 2. Middle rectal arteries. 





The ductus deferens unites with the duct of the seminal vesicle to form the ejaculatory duct which perforates the prostate gland to open into the prostatic urethra. An extensive malignant growth in the anterior wall of the vagina is most likely to involve the fundus of the bladder.

BLOOD VESSELS 

o

o





Branches of the internal iliac artery: From the posterior division: 1. Ilio-lumbar a. 2. Lateral sacral as. 3. Superior gluteal a. From the anterior division: 4. Umbilical a. which gives superior vesical a. then becomes obliterated forming the lateral umbilical ligament. 5. Obturator a. 6. Inferior vesical/Vaginal a. 7. Middle rectal a. 8. Inferior gluteal a. 9. Internal pudendal a. 10. Uterine a.

The inferior rectal vein is a tributary of the internal pudendal vein. The hemorrhoidal plexus is most likely to dilate in a patient with portal hypertension. Pressure in the portal vein is 8-10 8 -10 mmHg.

NERVES & PAIN 



Pain arising from the urinary bladder, uterus/cervix, vagina & rectum is felt in the pelvis along the mid-line from the pubic bone in front to the sacrum at the back. Pain arising from acute anal fissure is transmitted by the inferior rectal nerve.


Mahmoud Shoaib

38





The principal motor & sensory nerve of the perineum is the pudendal nerve (S2, 3 & 4). It may be injured by a stab into the ischio-rectal fossa 2 cm lateral to the anal canal. Pudendal nerve block is achieved by palpating the ischial spine vaginally to inject the anesthetic. The prostatic plexus of nerves originate from the pelvic splanchnics & its injury during prostatectomy causes loss of penile erection.

MISCELLANEOUS The ureter is crossed by the left colic vessels on the left side. It may be injured: 1. While clamping the uterine arteries during hysterectomy. 2. During excision of the right ovary as the ureter lies posterior to it.  

The pelvic diaphragm is formed by the: 1. Levator ani muscle (ilio-coccygeus, pubo-coccygeus & pubo-rectalis muscles): It arises from the tendinous arch of the fascia of obturator internus (arcus tendineus levator ani). 2. Coccygeus muscle. 



The perineum is divided into 2 triangles by a line connecting the ischial tuberosities.



The inferior part of the uro-genital diaphragm is called the perineal membrane.



The external anal sphincter lies immediately posterior to the perineal body.


Mahmoud Shoaib

39

DEVELOPMENTAL ANATOMY 1. 2. 3. 4. 5. 6.

Ecto-derm Epidermis of skin, nails & hair. Sweat, sebaceous & mammary glands. Nervous system. Pupillary muscle of the iris, lens & retina. Pineal body, posterior pituitary & adrenal medulla. Melano-cytes, Schwann cells & odonto-blasts.

Arch

Nerve

st

1 (mandibular)

5

th

Meso-derm

Endo-derm 1. Epithelium of the: GIT & its associated glands as well o as glandular cells of the liver & pancreas. Urachus & urinary bladder. o o Respiratory passages (pharynx, trachea, bronchi & alveoli). 2. Epithelial parts of the: Tonsils, thyroid, para-thyroids, o tympanic cavity & thymus. o Anterior pituitary.

Derivatives 

Summary

Malleus (& its anterior ligament) & incus (Meckel's



cartilage).

 

   

nd

2 (hyoid)

8

th

 

Mastication & mylo-hyoid. Spheno-mandibular ligament. Tensor tympani & palati. Anterior belly belly of di-gastric - Anterior part of tongue. Stapes & styloid process. Hyoid: upper part of body & lesser cornu.

  

  

rd

3

9

th

 

th

th

th

4 -6



st

10 (recurrent & superior laryngeal) nd





Facial expression. Stylo-hyoid & stapedius. Posterior belly belly of di-gastric. Hyoid: lower part of body & greater cornu. Stylo-pharyngeus. Thyroid, arytenoid, corniculate & cuneiform cartilages. Muscles of pharynx, larynx & palate.



   

3 M. 2 tensors. 2 anterior.

4 S. Facial. Hyoid. Posterior belly. S-ph. Hyoid. Cartilages. Muscles.

rd

1 , 2 & 3 arches contribute to structures above the lar ynx. th th  4 & 6 arches contribute to the larynx. th  5 arch exists transiently during embryological growth & development.

THE CIRCULATORY SYSTEM 



In early fetal life, the heart lies immediately below the mandibular arch & is relatively large. In the fetus, the valve of the IVC serves to direct the blood from that vessel through the foramen ovale into the left atrium.


Mahmoud Shoaib

40













At birth, left atrial pressure increases pushing the atrial septum premium against the septum secundum, functionally closing the foramen ovale. Its incomplete closure results in ASD. Incomplete fusion of the endo-cardial cushions results in AV septal defect.

The sinus venosus which is the large quadrangular cavity between the 2 vena cava in the embryonic human heart gives rise to the coronary sinus. The ductus arteriosus receives blood from the pulmonary artery. The right 4 th aortic arch forms the right sub-clavian as far as the origin of its i ts internal mammary branch. Complete failure of development of the spiral septum in the heart results in persistent truncus arteriosus in which the vessel never properly divides into the pulmonary artery & aorta.

THE GIT Derivatives of the meso-gastrium

Dorsal 1. Spleen. 2. Pancreas. 3. Greater omentum (gastro-phrenic, splenic & -colic ligaments). 4. Lieno (spleno)-renal ligament. 













Ventral 1. Liver & all ligaments associated with it (falciform, coronary & right & left triangular ligaments). 2. Lesser omentum (hepato-gastric & duodenal ligaments).

The mesenchyme of the pharyngeal arches forms the CT, lymphatic & blood vessels of the tongue. The mid-gut gives rise to the GIT from the duodenum (distal 1/2) to the transverse colon (proximal 2/3). The yolk sac is the 1 st element seen in the gestational sac during pregnancy as 5 weeks' gestation. It opens into the digestive tube by a long narrow tube, the vitelline duct. One of the vitelline duct anomalies is the umbilical fistula. The allantois is carried backward with the development of the hind-gut & then opens into the cloaca of terminal part of the hind-gut. Normal herniation of the gut in fetus is accompanied by anti-clock-wise rotation of the herniated gut loop. The neuro-enteric canal is a transitory communication between the neural tube & the primitive digestive tube. The ventral pancreatic bud forms part of the head & uncinate process of the pancreas.


Mahmoud Shoaib

41



Meckel's diverticulum is a blindly-ending pouch a few centimeters long on the antimesenteric border of the ileum within 100 cm of the ilio-caecal junction. It is a site of ectopic pancreatic or gastric tissue.

THE KIDNEY 



Meta-nephric glomeruli are derived from a distal (caudal) dorsal region of the mesoderm. Meso-nephric tubules are genital ridges next to the developing meso-nephros in a fetus & give rise to efferent ductules.

MISCELLANEOUS 





In meiosis, chiasmata separate during ana-phase I. ry

The ova (1 oocytes) are developed from the primitive germ cells which are embedded in the substance of the ovaries. The thyroid gland is developed from a median diverticulum that appears on the summit of the tuberculum impar.



The umbilical cord is filled with jelly of Wharton.



The fetal portion of the placenta consists of the villi of the chorion laeve. Week th

4

th

5

Month nd 2 th

4

7th 9th

Events 1. The amnion contains liquor amnii. 2. The cerebral hemi-spheres appear as hollow buds. 3. The heart tube is formed & the heart begins to beat. The cloacal tubercle is evident. 

 

 

The eyelids are present in the shape of folds above & below the eye. The loop of gut that projected into the umbilical cord is withdrawn within the fetus. The testis descends with the vaginal sac of the peritoneum. The baby weighs 3-3.5 Kg (6.5-8 lb).


Mahmoud Shoaib

42

PHYSIOLOGY &

PATHOLOGY


Mahmoud Shoaib

43

GENERAL PHYSIOLOGY & BLOOD ORGANELLES Structure 1. 2. 3. 4.

Function Transport between cells. Regression of uterine size after delivery. Protein synthesis.

Gap junctions Lyso-somes Rough ER Mito-chondria replicate spontaneously. It is the site of electron transport chain which is inhibited by atractyloside, so this drug has no effect on the function of RBCs as they do not contain mito-chondria.   

CELLS Cells 1. RBCs

o o

2. Neutro-phils.

o o

3. Eosino-phils. 4. Helper T-cells (CD 4) 5. Cyto-toxic T-cells (CD 8)

o

o o

o

6. Natural killer cells

o o

7. Mono-cytes

o o

8. Plasma cells 9. Mast cells 10. Dendritic (Langerhan's) cells 11. Kupffer cells in the liver 





Functions It is an example of permanent cells. RBCs count of men is > than that of women. The predominant WBC type (70%). ↓ number or functional defects in neutro-phils explains the cause of repeated pyogenic infections (e.g. strepto-coccal pneumonia). ↑ in patients with hydatid cysts. Activate other immune cells. Specific cellular defense mechanism with cyto -toxic activity. It has perforin in its granules. Host rejection of tumor cells. It has perforin in its granules. Become activated macro-phages. Have a large bi-lobed nucleus.

o

Production of Abs. Its granules contain heparin, histamine & chondroitin sulphate. APCs present in skin.

o

Re-cycling of old RBCs.

o o

Lympho-cytes & mono-cytes are most commonly seen in tissue undergoing chronic inflammation. Langhans giant cells are the hallmarks of granulomatous inflammation & are formed by the fusion of epithelioid cells (macro-phages) (e.g. tuberculosis). Giant cell is the most characteristic of the inflammatory response around a glass foreign body.


Mahmoud Shoaib

44

ANTI-BODIES (Abs) (IMMUNO-GLOBULINS)





G Highest percentage in a newborn. Most abundant Ab.



A In mucuscontaining areas.



M Largest Ab.



E It binds to allergens & triggers histamine release.

D

Pgs



D2 It is a 2 mediator of inflammation. ry







E2 It sensitizes nociceptive nerve endings causing pain. It relaxes bronchial smooth muscles.

F2α 



It contracts bronchial smooth muscles.



I2 It inhibits platelet aggregation.

It dilates blood vessels.

Arachidonic acid is one of the essential fatty acids required for the synthesis of Pgs.

COMPLEMENT







7

3b Opsonin (enhances phagocytosis). Anaphylatoxin.

 

5a 7 Chemo-tactic . Anaphylatoxin.



5b It initiates membrane attack complex (MAC).

The critical step in the elaboration of the biological functions of complement is the activation of C3.

Chemo-taxis is the uni-directional migration of WBCs towards a specific target.


Mahmoud Shoaib

45


Mahmoud Shoaib

46













Tenase complex = activated factors 8 + 9. 9. Coagulation factors are serine proteases except 5 + 8 (glycol-proteins) = 13 (transglutaminase).

Factor 5 can bind to activated platelets. Anti-thrombin III inactivates 2, 7, 9, 10, 11 & 12 & its deficiency predisposes to DVT & pulmonary embolism. Heparin which is normally produced by mast cells & baso-phils enhances the activity of anti-thrombin III. Hageman factor (factor 12) activates both the coagulation & kinin systems on contact with injured vascular basement membrane.

BLOOD TESTS

Control

 

Measures

PTT & aPTT 25 seconds. Intrinsic & common

 

PT & INR 12 seconds. Extrinsic & common

BT (bleeding time) 

Platelets, vessels & VWF

1

Clotting time

46

Tenase complex = activated factors 8 + 9. 9.



Coagulation factors are serine proteases except 5 + 8 (glycol-proteins) = 13 (transglutaminase).



Factor 5 can bind to activated platelets.



Anti-thrombin III inactivates 2, 7, 9, 10, 11 & 12 & its deficiency predisposes to DVT & pulmonary embolism.



Heparin which is normally produced by mast cells & baso-phils enhances the activity of anti-thrombin III.



Hageman factor (factor 12) activates both the coagulation & kinin systems on contact with injured vascular basement membrane.



BLOOD TESTS

Control

 

Measures the efficacy of

PTT & aPTT 25 seconds. Intrinsic & common pathways (8, 9, 10 & 12).

1.Heparin 1.Heparin use. 2.Anti-phospho2.Anti-phospholipid Ab. 3.↓ 3. ↓ coagulation factors (8, 9, 10 & 12) e.g. hemophilia.

Prolonged in

 

PT & INR 12 seconds. Extrinsic & common pathways (1, 2, 5, 7 & 10).

1.Liver 1.Liver disease. 2.↓ 2.↓ coagulation factors.

1

BT (bleeding time)

Clotting time

Platelets, vessels & VWF (required for platelet adhesion). 1.Thrombo-cyto1.Thrombo-cytopenia. 2.Aspirin 2.Aspirin use. 

1.Heparin 1.Heparin use. 2.↓ 2. ↓ fibrinogen. 3.Lupus 3.Lupus anticoagulant.

HEMO-PHILIA 2

    

A Factor 8. Haem-arthrosis. Normal PT & BT. ↑ PTT. Normal or ↑ VWF.



 

B Factor 9. Clinical bleeding.

 

C Factor 11. Autosomal recessive.

Owren para-hemo-philia 

Factor 5.

Factor 8 is synthesized by vascular endothelium & not by the liver.

1

Thrombin clotting time or thrombin time. Treated by infusion of factor 8 concentrate. Cholesterol crystals are seen within the joint space following episodes of pain. 2


Mahmoud Shoaib

47

CBC 1. MCV

2. MCH

3. MCHC



 

80-100 Fl.

 

25-35 pg/cell.

  

  

30-35 g/dL.



PLASMA PROTEINS



Albumin It is the most abundant & lightest plasma protein in terms of weight.

 

Fibrinogen 1.5-4 g/L in plasma. It is an acute-phase protein.

DRUGS 

Heparin-induced thrombo-cyto-penia is a thrombotic disorder whose risk is lower with LMWH which acts by inhibition of factor Xa.

ANEMIAS Iron deficiency anemia may be caused by: 1. Peptic ulcer (the most common cause in males). 2. Parasitic infestations. 

Anemia of chronic disease is characterized by: 1. ↓ serum iron & total iron-binding iron -binding capacity (TIBC). 2. ↑ serum ferritin. 

Sickle-cell anemia (hemoglobin S) is characterized by: 1. Destruction of circulating RBCs. 2. Auto-splenectomy (not palpable spleen). 



1. 2. 3. 4.

Vitamin B12 or folic acid deficiency causes pernicious anemia with ovoid RBCs rather than bi-concave-disc-shape. Megalo-blastic anemia is characterized by: Pan-cyto-penia. ↑ MCV. ↓ reticulo-cyte index. Hyper-segmented PMN neutro-phils.

β-thalassemia is characterized by: 1. Hypo-chromic anemia. 2. Splenomegaly. 3. Hemo-chromatosis. 


Mahmoud Shoaib

48

DISEASES 

Liver disease causes depression of normal coagulation system & excessive bleeding after surgery.

1. 2. 3. 4.

Poly-cythemia vera is characterized by: ↑ RBCs. ↑ WBCs. ↑ platelets. Splenomegaly.



Myelo-fibrosis causes massive splenomegaly.









1. 2. 3. 4.

ry

Platelets deficiency (thrombo-cyto-penia) causes a defect of 1 hemostasis (characterized by petechiae, purpura & epistaxis). Coagulation factors deficiency causes a defect of 2ry hemostasis (formation of fibrin). DIC is characterized by: ↑ D-dimer D-dimer assay (breakdown products of a fibrin mesh > 500 ng/ml ). Schisto-cytes (fragmented RBCs). ↑ PT & PTT. ↓ platelets.

Scurvery 1. Normal blood tests. 2. Skin & mucosal petechiae.





Anti-phospho-lipid syndrome 1. Normal blood tests. 2. Lupus anti-coagulants.

VW disease (autosomal dominant) 1. Bruising. 2. Bleeding from wounds. 3. Epistaxis. 4. Menorrhagia. 5. Normal PT, PTT & platelet count.

Grey platelet syndrome is characterized by thrombo-cyto-penia & large agranular platelets (deficient alpha granules). A LN excised from a boy with a sore throat & runny nose shows prominent, welldefined para-cortical follicles with germinal centers.

1. 2. 3. 4. 5. 6.

IMN (EBV infection) is characterized by: Pharyngitis. Fever, fatigue & malaise. Enlarged & tender LNs (e.g. cervical, axillary, inguinal, …). +ve mono-spot test. Atypical (re-active) lympho-cytes. Splenomegaly & mild hepatomegaly.



Mycosis fungoides is skin infiltration by neoplastic T-lympho-cytes.




Mahmoud Shoaib

49

Thrombotic thrombo-cyto-penic purpura 1. Fever. 2. Skin & mucosal petechiae.



Idiopathic thrombo-cyto-penic purpura Normal-sized spleen.

3. Renal insufficiency. 4. CNS disorder (e.g. mental confusion). 5. Thrombo-cyto-penia. 6. Platelet transfusion is contra-indicated. 7. Pink hyaline thrombi in small arteries.

OTHERS 



Erythro-poietin stimulates differentiation of erythroid-forming units (EFU-E) into colonyforming units (CFU-E). It is used in treating anemia of CRF & cancer chemo-therapy. 2+

3+

Iron is more effectively absorbed in the ferrous state (Fe ) than in the ferric state (Fe ). Dietary iron is more readily absorbed when ferritin stores of intestinal epithelium are low. Iron deficiency causes micro-cytic hypo-chromic anemia with moderate poikilo-cytosis. ↑ by strepto-kinase, uro-kinase & recombinant human TPA



Plasminogen

Plasmin. ↓ by ε-amino caproic acid





Platelet activating factor functions as a soluble signal messenger. Spectrin is a cyto-skeletal protein enabling RBCs to withstand stress on its plasma membrane.



After hemolysis, bilirubin level & reticulo-cytic reticulo- cytic count are ↑.



Immune-globulin D is given to Rh -ve women after delivery of Rh +ve baby.









After a trip to the Himalayas, a person complains of headache & peripheral cyanosis due to physiological poly-cythemia.

Citrate is the preferred anti-coagulant for blood storage. 2+ It combines with Ca forming un-ionized Ca complex. The myeloid -erythroid ratio of bone marrow of a voluntary bone marrow donor should be 3:1. Substances with high oil:water partition co -efficient readily permeates cell membranes e.g. O2, Co2 & steroid hormones.


Mahmoud Shoaib

50

NERVE 











+

During activation of a nerve cell membrane (action potential), Na ions flow inward.

The re-polarization phase is a result of ↓ Na+ permeability & rapidly ↑ K + permeability. Voltage-gated Na+ channels have specialized trans-membrane domains (S4) that sense trans-membrane voltage. K+ channels are responsible for the resting membrane potential of vascular smooth muscle cells. + + Na /K pump generates the ion gradient across ac ross the cell membrane. -

Opening Cl channels in a neuronal membrane causes hyper-polarization to -70 mv. Resting membrane potential of a neuronal cell body is -60 mv. Nerve gas (organo-phosphate) causes respiratory & CV failure by decreasing the rate of rhythmicity of SAN by inducing hyper-polarization.

MUSCLE 





Miniature end-plate potential represents opening of multiple ion channels in the muscle membrane caused by spontaneous release of a small amount of neuro-transmitter. Myo-globin acts like hemo-globin & binds with O 2. It does not exhibit co-operative binding of O 2 (not affected by O 2 pressure) giving a hyper-bolic O2 dissociation curve. Troponin is a protein involved in skeletal but not smooth muscle contraction (instead, there is calmodulin in smooth muscles). Ca2+ initiates contraction by binding to it. 2+



↓ extra-cellular Ca inhibits release of vesicles at all types of synapses.



Stretch reflex is mono-synaptic.



Golgi tendon organ reflex causes inhibition of motor neurons.







A burst of vigorous physical activity (seconds-minutes) requires energy which is derived from the breakdown of glycogen to lactic acid (faster sources than ATP & creatine phosphate). Malignant hyper-thermia with halothane is caused by increased heat production by skeletal muscles. It is treated by a ryanodine receptor (e.g. dantrolene which is a muscle relaxant). Adrenaline stimulates β-receptors inducing lipolysis.


Mahmoud Shoaib

51



 

Acetyl-choline release at the NMJ causes post-synaptic depolarization due to increased + + post-synaptic membrane permeability to small cations (Na & K ). Type II (fast-twitch) Use anaerobic metabolism. Rich in glycogen.

Type I (slow-twitch)  


Mahmoud Shoaib

52

FLUIDS, ELECTROLYTES & ACID-BASE BALANCE RENAL SYSTEM EQUATIONS 

Fluid movement "Starling forces" = = K (capillary hydro-static pressure – pressure – inter-stitial inter-stitial h.p.) – (capillary – (capillary colloid osmotic pressure - inter-stitial c.o.p.). K = capillary filtration coefficient = 1 .     



Clearance =

o

It is ↓ after kidney donation. Inulin clearance = GFR (120 ml/min) as it is freely filtered, not secreted nor absorbed. Glucose clearance = 0 as it is completely absorbed & not secreted).

o

 

GFR is ↑ by: 1. Efferent arteriolar constriction. 2. ↑ RBF. 3. ↑ glomerular capillary glomerular capillary hydro-static pressure. 



o

RPF =

            

PAH (Para-Amino Hippuric acid) is completely removed from the plasma in a single pass through the kidney (about 80% of it is secreted at the tubules), so it is used for measuring RPF (650 ml/min = GFR X 5).



Excretion = (filtration + secretion) – secretion) – re-absorption. re-absorption.



– (Cl + HCo 3 ) = 8-16 mmol/L. Anion gap = (Na + K ) – (Cl

+

 

   

+

=

-

-

 

FLUIDS & ELECTROLYTES Total body water (TBW) = 60% of body weight (45 L for a 75 Kg man) Extra-cellular fluid Intra-cellular fluid Percentage  40% (15 L).  60% (30 L). 1. Glucose. 1. Amino acids. + + +2 +2 Rich in 2. Na . 2. K , Ca & Mg . -3 -3 -2 3. Cl & HCo . 3. Po4 & So4 .

Infusion of a hyper-tonic saline solution causes: 1. ↑ extra-cellular extra-cellular & intra-cellular osmolarity. 2. ↑ extra-cellular extra-cellular fluid volume. 3. ↓ intra-cellular intra-cellular fluid volume. 

Infusion of water for fluid & salt loss (e.g. after excessive sweating) causes: extra-cellular fluid volume. 1. ↓ extra-cellular 2. ↑ intra-cellular intra-cellular fluid volume. 3. The most appropriate initial therapy is IV administration of iso-tonic normal saline. 


Mahmoud Shoaib

53 +

Normal ↓

+

Na 135 – 135 – 145 145 mEq/L. 1. Diuretics. 2. ↓ ADH. 3. Diarrhea, sweating, burns … 4. Addison's disease.

K 1 3.5 – 3.5 – 4.5 4.5 mEq/L . 1. Diuretics. 2. Renal tubular disorders. 3. Diarrhea, vomiting … 4. Hyper-aldosteronism. 5. Cushing's syndrome. 6. Liddle syndrome.





 Eu-volemic hypo-natremia:

psychosis. It is associated with ↑ synthesis of ammonia in the kidneys.

 Hyper-volemic hypo-natremia:

Edematous disorders (e.g. cirrhosis). 1.Patients 1.Patients on osmotic cathartics. 2.Hyper-alimentation 2.Hyper-alimentation (hypervolemic hyper-natremia).

o

↑



Acidosis.

2+



o o

Normal plasma mg concentration is 0.7-1.05 mmol/L (1.4-2.1 mEq/L). Hyper-magnesemia with CRF is characterized by respiratory depression. Hypo-magnesemia is characterized by hypo-calcemia (seizures). 3-



Normal plasma Po4 level is 0.8-1.45 mmol/L. Hyper-phosphatemia is characterized by metastatic calcification.



Only 1% of Ca is available for buffering changes in Ca balance in the body.



+2

+2

ARTERIAL BLOOD ACID-BASE DATA -

7.35 – 7.35 – 7.45

PCo2 (mmHg) 35 - 45

HCo3 (mmol/L) 22-26

pH 

Normal



Partially compensated metabolic acidosis

↓

↓

↓

Partially compensated metabolic alkalosis (e.g. persistent vomiting or naso-gastric suctioning → hypo-chloremic)

↑

↑

↑

↓

↑

Normal











Respiratory acidosis (e.g. acute exacerbation of COPD or hypo-ventilation) Fully compensated respiratory acidosis

Normal

Uncompensated respiratory alkalosis Fully compensated respiratory alkalosis

↑ Normal

acidosis Mixed acidosis  Mixed alkalosis alkalosis 

1

↓ ↑

↑ (hypo-ventilation)

↓ (hyper-ventilation)

↓ (hyper-ventilation)

↑ ↓

↑ Normal ↓ ↓ ↑

Intra-cellular concentration is 150 mmol/L.


Mahmoud Shoaib

54





-

Persistent diarrhea causes ↑ H+ secretion by secretion by the distal tubule.

Metabolic acidosis with ↓ anion gap 1. Hypo-albuminemia Hypo-albuminemia (↓ anions). +2 +2 2. ↑ Ca , Mg & gamma globulins (↑ cations). 3. Hyper-viscosity. 4. Lithium or halide (bromide or iodide) intoxication.

5. 6. 7. 8.

+

Metabolic acidosis is caused by severe severe diarrhea (↓ HCo (↓ HCo3 ) or renal disease (↑ H ). It is treated by NaHCo3 .



Metabolic acidosis with a normal anion gap Uretero-sigmoidostomy.

Metabolic acidosis with ↓ anion gap Hypo-albuminemia Hypo-albuminemia (↓ anions). +2 +2 ↑ Ca , Mg & gamma globulins (↑ cations). Hyper-viscosity. Lithium or halide (bromide or iodide) intoxication.

Metabolic acidosis with ↑ anion gap 1. Hyper-albuminemia. +2 +2 2. ↓ Ca & Mg . 3. Uremia. 4. Lactic acidosis.

Metabolic acidosis with ↑ anion gap 5. Hyper-albuminemia. +2 +2 6. ↓ Ca & Mg . 7. Uremia. 8. Lactic acidosis.

Lactic acidosis is classified into: 1. Type A occurs with poor tissue perfusion or oxygenation. 2. Type B is further divided into: 1) Type B1 occurs with systemic diseases (e.g. renal & hepatic failure, diabetes & malignancy). 2) Type B2 is caused by several drugs & toxins. 3) Type B3 is caused by inborn errors of metabolism. 







+

Metabolic alkalosis due to intra-cellular shift of H ions occurs with hypo-kalemia. Severe metabolic alkalosis associated with profuse vomiting causes ↓ cerebral perfusion. +

Loss of fluid from the colon causes acidosis & hypo-kalemia as it secretes K .

BBB  

It is more permeable in infants & breaks down in infected areas. It allows the passage of: 1. Lipid-soluble substances (O2, Co2, ethanol & steroid hormones). 2. Substances having transport systems (sugars & some amino acids). 3. Serotonin (5HT).


Mahmoud Shoaib

55

DISEASES 

1. 2. 3. 4. 5. 

Nephrotic syndrome is characterized by: Proteinuria (> 3.5 gm/day) causing hypo-albuminemia hypo-albuminemia & ↓ oncotic pressure. pressure, salt & water retention by the diseased kidney Edema occurs due to ↓ oncotic pressure, & congestive heart failure. Hyper-cholesterolemia. Coagulation abnormalities. 1 Oval fat bodies in urinalysis specimen (characteristic). Minimal-change disease (MCD) is the most common cause of nephrotic syndrome in children (4-8 years).

Group A strepto-coccal sore throat causes acute nephritic syndrome (glomerulonephritis) which is characterized by: 1. Generalized body edema. 2. Hypertension. 3. Hematuria. 

Disease 1. Rapidly progressive glomerulo-nephritis 2. Goodpasture's syndrome 2

3. SLE

o

o

o

Biopsy (pathology) Extensive glomerular crescent formation. A linear pattern of immune-globulin deposition along the glomerular basement membrane. Sub-endothelial granular electron-dense deposits.

Pre-eclampsia is characterized by: 1. Hypertension (2 readings at least 6 hours apart > 140/90 ). 2. Proteinuria (> 300 mg/day). 3. Edema of hands & feet. 

Hyper-aldosteronism is characterized by: 1. Hypertension & hypo-kalemia. 2. Aldosterone > 15 ng/dL. 3. Aldosterone/renin ratio > 20. 

Hypo-aldosteronism is characterized by: + 1. ↓ serum & ↑ urinary Na . + 2. ↑ serum & ↓ urinary K . 3. ↓ serum HCo 3 . 



Pelvic floor muscle weakness (e.g. after prostatectomy) causes stress incontinence.

Aldosteronism: ry 1. 1 : ↓ renin. ry 2. 2 : ↑ renin (caused by heart failure & renal artery a rtery stenosis). 

1

They appear with pronounced proteinuria & lipiduria. In such cases, therapy depends on the severity & na ture of the renal disease so a per-cutaneous needle biopsy of the kidney is appropriate & helpful. 2


Mahmoud Shoaib

56

Destruction of the supra-optic nuclei of the brain causes ↓ ADH secretion which causes ↓ water reabsorption in DCTs & collecting ducts with resultant ↑ urinary volume & a very dilute urine.



+

↑ K , BUN & creatinine (CRF) indicate hemo-dialysis. Patients in RF who cannot be dialysed should be given a TPN solution without amino acids. 1 Metabolic acidosis (↓ HCo3 ) & hyper-kalemia are the most life-threatening in ARF.





The diffuse form of scleroderma is characterized by: 1. Hyper-plastic arteriolo-sclerosis. 2. Malignant hyper-tension. 3. Fibrinoid necrosis, petechial hemorrhages & micro -infarcts in the kidneys. 



1. 2. 3. 1. 2. 

1. 2. 3. 4.

The most common causes of acute tubular necrosis (ATN) are: Hypo-tension (e.g. during a prolonged operation). Nephron-toxins (e.g. amino-glycoside anti-biotics & ethylene glycol). Septic shock. It is characterized by: ↑ serum & urea creatinine. c reatinine. Granular & hyaline casts in urinalysis specimen.

Acute tubule-inter-stitial nephritis (acute pyelo-nephritis) is characterized by: Dull pain in the lower back. Burning dys-uria. Leuco-cytosis with left shift. WBC casts (characteristic).

A ureteric calculus is characterized by: 1. Sudden-onset, severe, flank pain that comes in waves. 2. The urine contains blood but few WBCs with ↑ acidity & normal specific gravity. 





Bladder exstrophy carries the greatest significance in terms of morbidity among other congenital anomalies of the urinary tract. Sexually transmitted urethritis, cervicitis, proctitis & pharyngitis infections that are not due to gonorrhea are caused c aused predominantly by chlamydia & infrequently by mycoplasma or urea-plasma (non-gonococcal infections).

Myo-globinuria is usually associated with rhabdo-myo-lysis (muscle destruction – destruction – ischemia-re-perfusion injury). It is characterized by: 1. +ve urine dipstick test for blood. 2. -ve RBCs. 

1

Oral enalapril (ACE inhibitor) is contra-indicated in its treatment.


Mahmoud Shoaib

57

DRUGS 

A drug bound to plasma proteins has ↓ renal excretion.



Solution of choice for parenteral nutrition is crystalline amino acids.



Thiazide & loop diuretics cause hypo-kalemic metabolic alkalosis (↓ H ).



K-sparing diuretics oppose the action of aldosterone.

+

MISCELLANEOUS 











Squamous epithelium is normally not seen above the outer urethra (it is lacking in the renal cortex & medulla). Renal concentrating ability is reflected by the specific gravity (1.002-1.028 g/ml). The most important physiological function of the lymphatic system is to transport fluid & proteins from inter-stitium to blood.

Transport maximum (Tm) is the point at which ↑ concentration does not ↑ the movement of a substance across a membrane. For glucose, it is 300 mg/dL. Plasma & inter-stitial fluid are very similar except for RBCs, platelets & plasma proteins which cannot pass through capillaries. Angiotensin II is a powerful dipsogen hormone which stimulates thirst.

Juxta-glomerular apparatus consists of: 1. Extra-glomerular mesangial (lacis) cells. 2. Macula densa of DCT. 3. Juxta-glomerular cells of afferent arteriole. It controls blood pressure through production of renin (renin-angiotensin-aldosterone 1 system) . 

1

Its destruction causes hyper-kalemia.


Mahmoud Shoaib

58


















PCT is particularly vulnerable to ischemic damage. H+ secretion is coupled to Na + & HCo3- re-absorption (85% in PCT). +

↓ Na re-absorption causes ↑ urinary volume. From DCT & on, K + is secreted & influenced by aldosterone. K+ secretion is the main cause + of ↑ renal excretion of K . In case of dehydration (e.g. hemorrhage), CDs re-absorb 24% of filtered water instead of 5% in normal circumstances.

Transport of glucose, amino acids & phosphate occurs ry through 2 active transport + with Na . Osmolality is measured by mosmol/L.

Mahmoud Shoaib

59

Hormone

Trigger & pathway 

Hypotension → synthesis.



↑ atrial pressure → release.



↓ Ca .

1. Angiotensin II

2. Atrial natriuretic peptide (ANP) 3. Vitamin D3 (calcitriol) 4. Parathyroid hormone (PTH)

   

5. Aldosterone

 

6. Antidiuretic hormone (ADH)

  

2+

2+

↓ Ca . 3↑ Po4 . ↓ vitamin D. Hypo-volemia. Hypo-tension (via Ang II). + ↑K . Hypo-volemia. Hypo-tension (via Ang II). ↑ plasma osmolality.

Physiologic hormones affecting the kidney Site of action in the nephron Net effect (see figure) 1.Afferent 1.Afferent & efferent (higher degree) arteriolar o Afferent & efferent arterioles. constriction leading to ↑ GFR. + 2.Compensatory 2.Compensatory Na absorption occurs in the proximal as well as the distal nephron to maintain fluid balance (via + water osmosis following Na ). 1.Afferent 1.Afferent arteriolar dilation & efferent arteriolar o Afferent & efferent arteriole. + constriction leading to ↑ GFR & Na filtration. o DCT. + 2.At 2.At the DCT, it inhibits Na uptake to ensure volume loss. 2+ o DCT. uptake.  ↑ Ca

Ascending limb of LoH. o DCT. o

2+



↑ Ca uptake.

+

+

o

CD.



↑ Na uptake & K excretion causing net fluid retention.

o

CD.



↑ free water uptake from the CD.

59

Hormone

Trigger & pathway 

Hypotension → synthesis.



↑ atrial pressure → release.



↓ Ca .

1. Angiotensin II

2. Atrial natriuretic peptide (ANP) 3. Vitamin D3 (calcitriol) 4. Parathyroid hormone (PTH)

   

5. Aldosterone

 

6. Antidiuretic hormone (ADH)

  

2+

2+

Physiologic hormones affecting the kidney Site of action in the nephron Net effect (see figure) 1.Afferent 1.Afferent & efferent (higher degree) arteriolar o Afferent & efferent arterioles. constriction leading to ↑ GFR. + 2.Compensatory 2.Compensatory Na absorption occurs in the proximal as well as the distal nephron to maintain fluid balance (via + water osmosis following Na ). 1.Afferent 1.Afferent arteriolar dilation & efferent arteriolar o Afferent & efferent arteriole. + constriction leading to ↑ GFR & Na filtration. o DCT. + 2.At 2.At the DCT, it inhibits Na uptake to ensure volume loss. 2+ o DCT. uptake.  ↑ Ca

Ascending limb of LoH. o DCT.

↓ Ca . 3↑ Po4 . ↓ vitamin D. Hypo-volemia. Hypo-tension (via Ang II). + ↑K . Hypo-volemia. Hypo-tension (via Ang II). ↑ plasma osmolality.

o

2+



↑ Ca uptake.

+

+

o

CD.



↑ Na uptake & K excretion causing net fluid retention.

o

CD.



↑ free water uptake from the CD.


Mahmoud Shoaib

60

Diuretics

Diuretic type (example) 1. Carbonic anhydrase inhibitor (acetazolamide)

o

Site of action PCT.





 

2. Osmotic (mannitol)

o

PCT.

3. Loop (furosemide)

o

LoH.



o

DCT.



o

CD.



 

4. Thiazide (hydro-chlorothiazide) 5. K+ Sparing: 1) Aldosterone Antagonists (spironolactone). 2) Epithelial Na+ channel (ENaC) blocker (amiloride & triamterene).

 

  

Mechanism (see figure) CA is an enzyme involved in the breakdown of H2Co3 in the following reaction: H2O + CO2 ←CA→ H2CO3 ↔ HCO3- + H+. +

Under physiologic conditions, filtered HCO 3 combines with H ions to generate H2CO3, which is acted on by CA to make CO2 & H2O. As CO2 diffuses into the tubular cells, more HCO3 is absorbed from the serum. In the presence of acetazolamide, CA is inhibited, allowing for H2CO3 to build up in the tubules & + hence urinary HCO 3 wasting (H alternatively is reabsorbed via a different pathway). This leads to a + ↓ ability to reabsorb Na in exchange for H+ leading to mild diuresis. Mannitol is filtered through the glomerulus but cannot be reabsorbed. This ↑ the osmolality of the filtrate & w ater is retained in the tubules to ensure urine osmolality. + + + Blocks the Na -K -Cl pump (NKCC) in the thick ascending limb of LoH allowing for more Na & subsequently fluid loss from the nephrons. They block the activity of Na +-Cl- channels in the DCT allowing more Na+ & water loss. Aldosterone acts on the cells of CDs & induces expression of Na/K exchangers & ENaC. This allows for the exchange of Na+ for K+ (Na+ enters the tubular cells & K + is lost in the urine). Aldosterone antagonists competitively inhibit the action of aldosterone on the principal cells & + therefore ↓ the expression of the exchanger. With the lack of Na uptake from the nephrons & loss in the urine, diuresis also occurs. +

Aldosterone also controls expression of ENaC channels in the DCTs to absorb Na . + + Inhibition of the ENaC ↓ Na uptake & K loss from the tubular ce lls. + Loss of Na in the urine leads to mild diuresis.

60

Diuretics

Diuretic type (example) 1. Carbonic anhydrase inhibitor (acetazolamide)

o

Site of action PCT.





 

2. Osmotic (mannitol)

o

PCT.

3. Loop (furosemide)

o

LoH.



o

DCT.



o

CD.



 

4. Thiazide (hydro-chlorothiazide) 5. K+ Sparing: 1) Aldosterone Antagonists (spironolactone). 2) Epithelial Na+ channel (ENaC) blocker (amiloride & triamterene).

 

  

Mechanism (see figure) CA is an enzyme involved in the breakdown of H2Co3 in the following reaction: H2O + CO2 ←CA→ H2CO3 ↔ HCO3- + H+. +

Under physiologic conditions, filtered HCO 3 combines with H ions to generate H2CO3, which is acted on by CA to make CO2 & H2O. As CO2 diffuses into the tubular cells, more HCO3 is absorbed from the serum. In the presence of acetazolamide, CA is inhibited, allowing for H2CO3 to build up in the tubules & + hence urinary HCO 3 wasting (H alternatively is reabsorbed via a different pathway). This leads to a + ↓ ability to reabsorb Na in exchange for H+ leading to mild diuresis. Mannitol is filtered through the glomerulus but cannot be reabsorbed. This ↑ the osmolality of the filtrate & w ater is retained in the tubules to ensure urine osmolality. + + + Blocks the Na -K -Cl pump (NKCC) in the thick ascending limb of LoH allowing for more Na & subsequently fluid loss from the nephrons. They block the activity of Na +-Cl- channels in the DCT allowing more Na+ & water loss. Aldosterone acts on the cells of CDs & induces expression of Na/K exchangers & ENaC. This allows for the exchange of Na+ for K+ (Na+ enters the tubular cells & K + is lost in the urine). Aldosterone antagonists competitively inhibit the action of aldosterone on the principal cells & + therefore ↓ the expression of the exchanger. With the lack of Na uptake from the nephrons & loss in the urine, diuresis also occurs. +

Aldosterone also controls expression of ENaC channels in the DCTs to absorb Na . + + Inhibition of the ENaC ↓ Na uptake & K loss from the tubular ce lls. + Loss of Na in the urine leads to mild diuresis.


61

CVS EQUATIONS & LAWS 

(systolic – diastolic). diastolic). Mean arterial blood pressure = diastolic + 1/3 (systolic –



CO =



CO =

            –      

o

CO (ml/min) = HR X SV (heart rate X stroke volume). 15% of CO is received by brain. 2% of CO is received by skin. 2% of CO is received by bronchial circulation.



CO of the right ventricle ↑ during deep inspiration.



Flow =



o o

  

Mahmoud Shoaib

61

CVS EQUATIONS & LAWS 

(systolic – diastolic). diastolic). Mean arterial blood pressure = diastolic + 1/3 (systolic –



CO =



CO =

            –      

o

CO (ml/min) = HR X SV (heart rate X stroke volume). 15% of CO is received by brain. 2% of CO is received by skin. 2% of CO is received by bronchial circulation.



CO of the right ventricle ↑ during deep inspiration.



Flow =



SVR = (MAP -



Cardiac index is related to body surface area.



o o





    

) X 80.

The Frank-Starling law of the heart states that: within physiological limits, the heart pumps all the blood that comes to it. ↑ (e.g. by a vaso-constrictor agent) within physiological limits, the stroke So, if the EDV ↑ (e.g. volume ↑. According to Poiseuille-Hagen formula, increasing the diameter of a vessel to twice the initial diameter would ↓ the vessel resistance to /6 of the initial resistance. So, if the resistance of a blood vessels is 16 PRU then doubling the vessel diameter would change the resistance to 1 PRU.



Pulse pressure is determined by the stroke volume (normally about 40 mmHg).



↑ systemic blood pressure leads to an ↑ in the residual volume of the left ventricle.



↑ pre-load pre-load (venous return) ↑ the ventricular wall tension & SV.



Left atrial pressure equals PAWP.


Mahmoud Shoaib

62

CARDIAC CYCLE 



Opening of the AV valves occurs at about the same time in the cardiac cycle as the beginning of diastole. st Their closure occurs at about the same time in the cardiac cycle as the 1 hear sound. Closure of the aortic valves producing the 2 nd heart sound occurs at the onset of the isovolumetric relaxation phase of the cardiac cycle.

JUGULAR VENOUS PULSE



A: right atrial contraction. C: bulging of the tri-cuspid valve into the right atrium (during right ventricular isovolumic systole). X: atrial relaxation & downward displacement of the tri-cuspid valve (during right ventricular systole). V: ↑blood volume in the vena cava & right atrium during ventricular systole the tricuspid valve is closed. Y: opening of the tri-cuspid valve & flow of blood into the right ventricle.



The v wave is equal to the a wave in patients with ASD.

 





NERVES & CONDUCTION SYSTEM 



Para-sympathetic nervous stimulation of the heart ↓ heart rate (slowing of the heart). Its inhibition ↑ heart rate. The SAN has the highest rate of automatic discharge. 2+ Phase 0 of an SA nodal action potential results from influx of Ca ions.



Ventricular filling occurs due to conduction delay in the AV node.



The rate of conduction of action potentials in Purkinje fibers is about 1.5-4 m/s.



A direct stroke to the left carotid sinus causes fainting due to ↓ firing rate of cardiac sympathetic fibers.


Mahmoud Shoaib

63







↑ sympathetic activity via renal nerves is a major stimulus for the release of renin from the juxta-glomerular apparatus. 2+

L-type Ca channels are responsible for the plateau phase of the cardiac action potential that is reflected by the Q-T interval. Loss of sympathetic tone in vessels of the arms or legs causes acute vaso-dilatation (e.g. cutting sympathetic nerve fibers).

ECG  Normal criteria:

1. P-wave: < 0.12 s. 2. P-R interval: 0.12-2 s. It is ↑ with ↓ conduction through the A-V A -V node. 3. Q-T interval: 0.4 s. 4. S-T segment: 0.08 s. 5. T-wave: ventricular re-polarization. Abnormality 1. Hypo-thermia. 2. Atrial fibrillation.

   

3. Peri-cardial effusion & peri-carditis. 4. Myo-cardial infarction (MI) 5. Failure of the AVN to conduct. +

6. ↓ K .

  

  

+

7. ↑ K . 2+ 8. ↑ Ca . 9. Very fast heart rate. 

 

Findings Sinus brady-cardia. Irregularly irregular pulse. Absent P-waves. Irregular P-R intervals. Small or low voltage QRS complexes. Elevated ST-segment. Independence of P-waves & QRS complexes. Depressed S-T segment (↓). (↓). Flattened (notched) T-waves. Prominent (elevated) U-waves. Tented T-waves (↑). (↑). Short Q-T interval.

A myo-cardial infarction involving the inferior wall of the heart is picked up by leads II, III & aVF.

DISEASES 



Following severe hemorrhage, transfusion of blood ↓ the total peripheral resistance.

Kidneys are especially vulnerable during shock (prolonged hypo-tension) while skeletal muscles are most likely to sustain the least damage.

Cardiogenic shock is characterized by: 1. ↑ pre-load, PAWP, CVP & vascular resistance. 2. ↓ CO & mixed venous O 2. 


Mahmoud Shoaib

64



1. 2. 3. 4.  



o



Tetralogy of Fallot is characterized by: VSD. RVOTO (pulmonary stenosis). Over-riding aorta. RV hyper-trophy. X-ray: small boot-shaped heart & ↓ pulmonary vascular markings. A pulsus paradoxus is an exaggeration of the normal variation in the pulse during by > 10 mmHg during inspiration. respiration in which systolic pressure ↓ by > Non-bacterial thrombotic endocarditis (NBTE) is the deposition of small sterile vegetations on valve leaflets. The previous term was marantic endocarditis, from the Greek marantikos, meaning “wasting away”. Risk factors: 1. Wasting diseases. 2. DIC. 1 3. Previous rheumatic fever . 4. Mucin-producing metastatic carcinomas (of lung, stomach or pancreas). 5. Chronic infections (e.g. tuberculosis). Giant-cell (temporal) arteritis is the most common form of systemic vasculitis in adults.

Thrombo-angitis obliterans (Buerger's disease) is an inflammatory thrombosis of small & medium-sized arteries causing ischemia in distal extremities. Tobacco use is the 1 ry risk factor. It is characterized by: 1. Severe pain in both legs even at rest. 2. Chronic ulceration of toes. 



Pheo-chromo-cytoma is a catecholamine-secreting tumor of chromaffin cells typically located in the adrenals. It is benign in > 90% of cases.

1. 2. 3. 4. 5.

Pulmonary embolism is characterized by: Sudden onset chest pain, dysnea, tachypnea & anxiety. Accentuated pulmonary S2. Leuco-cytosis. ↑ ventilation/perfusion ratio. ↑ pulmonary vascular resistance.



It is treated by a fibrino-lytic (thrombo-lytic) agent.



1

During the acute phase of rheumatic fever, the characteristic inflammatory lesions found in the heart are known as aschoff's bodies.


Mahmoud Shoaib

65



1. 2. 3. 4. 5.

Acute aortic dissection is characterized by: Cystic medial necrosis. Hyper-tension. Sudden onset of tearing chest pain that radiates to back & arms. No pressure reading from the left arm. A murmur of aortic insufficiency.

Acute peri-carditis is characterized by: 1. Peri-cordial friction rub. 2. ST-segment elevation. 3. No pathological Q waves. 







st

The leading cause of death after the 1 post-transplantation year is allo-graft coronary artery disease (coronary athero-sclerosis causing ischemia).

Eisenmenger syndrome is the process in which a left-to-right shunt in the heart (e.g. VSD) causes ↑ flow through thr ough the pulmonary vasculature, causing pulmonary hypertension, which in turn causes ↑ pressure in the right side of the heart & reversal of the shunt. A tumor of the right atrium & cardiac tamponade cause systemic edema, congestion of the systemic veins & ascites.

MISCELLANEOUS 







Ejection fraction is normally > 60%. Carotid body stimulation causes stimulation of the respiratory center. th If the 9 CNs are blocked bilaterally in the neck, the subject will no longer respond to hypoxia (↓ O 2) by causing an ↑ respiratory minute volume. ↓ CO ↑ pulmonary vascular resistance & ↓ pulmonary artery pressure. Obstruction of venous return to the right side of the heart causes the CO to fall & systemic arterial BP to ↑ as compensation.

1. 2. 3. 4.

↓ blood (ECF) volume (e.g. hemorrhage) he morrhage) causes: ↑ sympathetic nerve activity. ↑ plasma ADH (vaso-pressin). (vaso-pressin). Stimulation of baro-receptor baro-receptor reflex to ↑ the blood pressure. Constriction of skin vessels.



Angiotensin II ↑ blood pressure acutely & causes hypo-kalemia hypo-kalemia chronically.







↑ systemic arterial systemic arterial pressure from 100 to 300 mmHg ↑ the resistance to blood flow in the cerebral circulation. Under resting conditions, a marathon runner has a higher SV compared to un-trained people.


Mahmoud Shoaib

66

Vaso-dilation 2ry to the effects of local metabolites is the most important for maintaining ↑ blood flow to the athlete's skeletal muscles. If a blood sample is withdrawn from the pulmonary artery, it will show the following criteria: 1. 70% O2 saturation. 2. 12-24 mmHg pressure. 







Heart rate ↓ during an exercise which involves iso-metric muscle contractions. Under normal (basal) conditions, most of the energy used by the cardiac muscle comes from the metabolism of fatty acids. Sympathetic stimulation of the arterioles (e.g. after a major trauma) causes the greatest ↑ in total peripheral resistance as they represent 1/2 of the resistance of the systemic circulation.



Digoxin is a +ve inotropic agent that ↑ contractility of the heart.



Tissue cooling ↓ O 2 extraction by tissues.



A regular tachy-cardia due to a small ventricular postero-septal infarct indicates that the infarct has involved only a localized region of ventricular myo-cardium.



The left coronary flow peaks in early diastole.



A valvular lesion is best assessed by echo-cardio-graphy.



Duplex scan has > 90% sensitivity & >95% specificity for thrombus in DVT.



Turbulence in a blood vessel is more likely to occur if the velocity of blood within the vessel ↑.

Creatine kinase (CK) has 3 different iso-enzymes: 1. MM which is expressed by skeletal muscles (98%) & cardiac muscles ( 70%). 2. BB occurs mainly in tissues & its levels rarely have any significance. 3. MB which is expressed by skeletal muscles (1%) & cardiac muscles (30%). 



Endo-thelin is a naturally-occurring peptide that produces intense vaso-constriction.


Mahmoud Shoaib

67

RESPIRATORY SYSTEM EQUATIONS & LAWS 

o o

Compliance =

          

Palv = ambient atmospheric pressure = zero reference pressure. Ppl = -ve intra-pleural pressure.



↑ Lung surfactant (it also enhances alveolar stability ).



Boher's equation states that:

o

o



ARDS.



      



  

=

By Fowler's method, 

↓

 

= 0.25.

Driving pressure is the difference between inflow & outflow pressure. Pulmonary driving pressure = pulmonary arterial pressure (P a) – left – left atrial pressure (PLA) = 15 – 15 – 5 5 = 10 mmHg. Systemic driving pressure = aortic pressure (P a) – right – right atrial pressure (P RA) = 100 mmHg.

LUNG VOLUMES



The residual volume cannot be measured directly with a spiro-meter.



Total ventilation = RR X tidal volume.


Mahmoud Shoaib

68



o

o





Alveolar ventilation = RR (tidal volume - anatomical dead space). To cause the greatest ↑ in alveolar ventilation in a man who is swimming & breat hing though a snorkel, ↑ the tidal volume by 2 folds & use a shorter snorkel. If alveolar ventilation is halved (& if Co 2 production remains unchanged), then arterial & alveolar Co2 pressures will double. To calculate Inspiratory reserve volume: tidal volume, vital capacity & expiratory reserve volume must be known.

To correct respiratory alkalosis, you should ↓ the tidal volume.

DISEASES 

Lobar pneumonia is usually community-acquired. The most commonly identified pathogens are srepto-coccus pneumonia, hemo-philus influenza & atypical organisms.

α1-anti-trypsin deficiency is characterized by: 1. Pan-lobular pulmonary emphysema. 2. Liver cirrhosis. 



A lung abscess is seen on the X-ray as a mass lesion with air-fluid level.

Asbestosis is a form of inter-stitial pulmonary fibro sis seen in ship-builders & textile workers. X-ray may show: o 1. Linear reticular opacities, usually in the peripheral lower lobes. 2. Pleural plaques. 3. Honey-combing. 









1. 2. 3. 4. 

In pneumo-thorax, the most likely response upon entry of air into the chest would be c hest wall to spring outward. for the lung to collapse inward & the chest It is the most common problem associated with fine-needle aspiration from the lung. Pulmonary edema favors diffusion limitation of O 2 transfer from alveolar to pulmonary capillary blood. th

th

Transection of the afferent fibers of the 9 & 10 CNs (vagus & glosso-pharyngeal) results in prolonged inspiration & shortened expiration. Cystic fibrosis is characterized by: Being autosomal recessive. The gene that is abnormal encodes a cAMP-regulated Cl channel. ↑ sweat Cl . A greater risk for the development of bronchiectasis. ARDS is a diffuse pulmonary parenchymal injury associated with non-cardiogenic pulmonary edema. It is characterized by ↓ lung compliance.


Mahmoud Shoaib

69

1. 2. 3. 4.

Sarcoidosis is characterized by: Fever, weight loss & shortness of breath. Hilar lymph-adenopathy. Diffuse pulmonary inter-stitial disease. Non-caseating granulomas in 1 or more organs & tissues.



De-compression sickness results from nitrogen bubbles in the body fluids.



Hypoxic hypoxia is the only form of hypoxia with ↓ PaO2.



Aspiration of the stomach contents results in chemical pneumonia.





 

  







Pulmonary nocardiosis caused by nocardia asteroids is an opportunistic infection in patients on high dosages of immune-suppressive medications. It causes a chronic abscessing pneumonia.

Total lung capacity Functional residual 1 capacity Residual volume FEV1/FVC Diffusion capacity of 2 CO2 (DLCo) Disease Asthma Anemia with normal lungs Mild Co poisoning

Obstructive lung diseases (e.g. COPD) ↑

Restrictive lung diseases ↓

↑

↓

↑ ↓

↓

↓

?

Asthma

↓ Normal or ↑

Finding      

o

↓

o

↓ PO2 of mixed venous blood.

o

↓ arterial O 2 concentration.

   

ratio.

The most common cause of: 1. Serous pleural effusion: congestive heart failure & hypo-albuminemia. 2. Chylo-thorax: mediastinal malignant lymphoma. 

MISCELLANEOUS Normal values: 1. Pleural fluid volume: 10 ml. Its glucose content is the same as the plasma glucose content. 2. Mean arterial pulmonary pressure: 15 mmHg (systemic is 90 mmHg). 3. O2 carriage: 20 ml/100 ml blood. 

4. Arterial O2 pressure is slightly < alveolar O2 pressure due to shunted blood. 5. About 70% of Co2 is transported to the lungs in the form of HCo3 . 1 2

It is the volume of gas in the lungs at the end of a normal expiration. It is affected by the volume of blood in the pulmonary capillaries.


Mahmoud Shoaib

70

6. Maximum amount of work of breathing is required to overcome elastance (compliance) "60-66%". 7. Pulmonary vessels can accommodate about 500 ml blood in an adult man. 

1. 2. 3. 4.  

Physiological changes due to a 2-year stay in the Himalayas (high altitude): ↑ ventilation (the ↑ in ventilation that occurs immediately after ascent ↑ still further over the course in the next 1-3 days. ↑pulmonary vascular resistance. ↑ number of mito-chondria mito-chondria in a muscle biopsy. ↑ renal excretion of HCo 3 .

Diaphragm & external inter-costals are muscles of i nspiration. Abdominal muscles & internal inter-costals are muscles of expiration.

O2-Hb dissociation curve 











One of the non-respiratory functions of the lungs is ectopic ACTH secretion.

Breathing 100% O 2 ↑ PaO2 to almost 670 mmHg. If the ↑ is as low as 125 mmHg, this indicates an anatomical right-to-left shunting. -

Acetazolamide ↑ urinary HCo3 & is used for prevention of mountain sickness. ↑ blood Co2 tension produces the most potent effect in stimulating the respiratory center & so increasing respiration. alveolar-capillary PO 2 gradient. A man competing in a 1500 m. running event show s ↑ alveolar-capillary Hypoxia causes pulmonary VC (which improves matching of ventilation & blood flow in some lung diseases) while nitric oxide causes pulmonary VD.


Mahmoud Shoaib

71







The airway resistance is ↓ by ↑ airway Co2. Cheyne-Stokes breathing is characterized by periods of waxing & waning tidal volumes separated by periods of apnea.

hyper-capnea (↑ PaCo2) affects respiration primarily by stimulating After ex-tubation, hyper-capnea the central (medullary) chemo-receptors.


Mahmoud Shoaib

72

GIT & HEPATO-BILIARY SYSTEM DIGESTION & TRANSPORT 



  







 

 



The breakdown of complex foodstuffs is accomplished by hydrolysis. When saliva is freshly formed at ultimate stimulation, its pH is 8. Its secretion is most dependent on vagal stimulation. The pH of the pancreatic juice is alkaline. Complex starches are mainly digested by enzymes secreted from the pancreas. The columnar epithelial cells of the pancreatic ducts secrete most of the aqueous component of the pancreatic juice where HCo3 content is greater in response to secretin (which stimulates HCO3- secretion from the pancreas & pepsinogen secretion). Abolition of the cephalic phase of pancreatic secretion occurs after vagotomy. In the stomach, chief cells release pepsinogen which is activated by acid pH & pepsin. After Gastrectomy, pepsin will be produced in inadequate amounts. + The stomach does not digest itself because the gastric mucosal cells transport H out of + the gastric mucosa causing ↓ local H concentration. Acetyl-choline Acetyl-choline ↑ gastric acid secretion. When acid secretion is stimulated in i n the stomach, the potential difference between mucosa & serosa falls to -20 mV. 2+

Ca is concentrated in hepatic bile in the gall-bladder where bile becomes more acidic. Intra-mural fats or amino acids in the intestine stimulate chole-cysto-kinin (CCK) release from the duodenum which causes sustained gall-bladder contractions & 1 relaxation of the sphincter of Oddi . In the presence of g all-stones, CCK action aggravates inflammation. Bile acids are derivatives of cholesterol synthesized in the hepato-cytes.



Stored fat is usually transported from one part of the body to another in the fo rm of free fatty acids. Chylo-microns have the highest content of tri-glycerides tri-glycerides (80%).



Lactase is secreted by the mucosa of the small sma ll intestine.





Amino acids are transported across the luminal surface of the intestinal epithelium by a + co-transport with Na . The essential amino acids must be present in the diet.



Intestinal peristalsis requires an intact myenteric nerve plexus.



Absorption: 1. Vitamin B12, electrolytes & bile salts in ileum. 2. Fat-soluble vitamins in jejunum. 3. Water in colon & ileum. 

1

CCK deficiency causes contraction of the sphincter of Oddi.


Mahmoud Shoaib

73

DISEASES Esophageal achalasia is characterized by: 1. Difficulty in swallowing solids & liquids. 2. Regurgitation of un-digested solids & liquids. 3. Dilatation of the terminal esophagus with loss of peristalsis in the distal 2/3. 



1. 2. 3. 4. 5.

CREST syndrome is characterized by: Calcinosis. Raynaud's phenomenon (fingers turn blue on cold exposure). Esophageal dys-motility. Sclero-dactyly (difficult fine movement of fingers because the skin becomes increasingly tight with mask face). Telangiectasia.

6. Weight loss. 7. +ve anti-nuclear Ab. 

Esophageal laceration (Mallory-Weiss syndrome) presents as a massive hematemesis after a prolonged bout of vomiting.

Duodenal ulcer disease is characterized by: 1. Pain in the upper central abdomen 2-3 hours after meals. 2. Waking up during the night with a similar pain. 



Gastrectomy causes iron-deficiency anemia because acid secretion by the stomach enhances iron absorption.

Vitamin B12 deficiency may occur due to: 1. Absence of parietal cells which secrete the intrinsic factor on which vitamin B 12 absorption depends on. 2. Complete resection of the ileum which is the site of its absorption. 







1. 2. 3. 4. 5.

Following total colectomy & ileostomy, the volume & water content of o f ileal discharge ↓ over time. Extension of an adeno-carcinoma of the colon to the serosa suggests a poor prognosis.

Aganglionosis in the rectum (aganglionic mega-colon or Hirschsprung's disease) is characterized by: Abdominal distension. Vomiting. Failure to pass meconium. X-ray shows markedly distended loops of small bowel & colon. At biopsy from the sigmoid colon: lack of mural ganglion cells.

Pancreatitis is characterized by: 1. Severe abdominal pain radiating to the back. 2. Markedly ↑ serum amylase. 


Mahmoud Shoaib

74

Acute appendicitis is characterized by: 1. Pain in the abdomen that started from the umbilical region & later shifted to the right lower abdomen. 2. Anorexia, nausea & fever. 3. Leuco-cytosis. 

Glycogen storage disease type I (Von Gierke's disease) is the most common of the glycogen storage diseases. It results from deficiency of the enzyme glucose-6-phosphatase. It is characterized by: 1. ↑ concentration of hepatic glycogen with normal structure. 2. No detectable ↑ in serum glucose from gluco-neo-genesis gluco -neo-genesis after oral intake of proteinrich diet. 

After an episode of hepatitis A, a liver biopsy shows normal architecture but with scattered loss of individual cells with the micro-scopic appearance of karyorrhexis & cell fragmentation.





HBeAg signifies active viral replication.



Mallory bodies are characteristically present in alcoholic hepatitis.



1. 2. 3. 4.

1ry biliary cirrhosis is characterized by: Pruritus. ↑ alkaline phosphatase level. +ve anti-mito-chondrial Ab. Absence of irregular regenerative nodules.

Micro-nodular cirrhosis is characterized by: 1. Ascites. 2. Clear, yellow ascetic fluid with a protein of 2.1 g/dl & contains a few metho-thelial & mono-nuclear cells. 



Gall-stones are composed mainly of cholesterol. Cholesterol gall-stones account for about 80% of gall-stones.

Jaundice: Pre-hepatic (e.g. hemo-lysis or Gilbert syndrome) 1. Anemia. 2. Un-conjugated hyper-bilirubinemia (↑ indirect bilirubin). 

1

Hepatic 1. ↓ plasma albumin. 2. Serum aminotransferase > 500 units.

1. 2. 3. 4. 5. 6.

Post-hepatic (obstructive) (e.g. blockage of the CBD or pancreatic head cancer) 1 Conjugated hyper-bilirubinemia. ↑ urine bilirubin urine bilirubin levels. ↓ urine uro-bilinogen uro-bilinogen levels. ↑ alkaline phosphatase. Pale stools. Deficiency of vitamin Kdependent clotting factors.

The most common cause of neonatal chole-stasis is extra-hepatic biliary atresia.


Mahmoud Shoaib

75

Crohn's disease 1. Right lower quadrant pain & tenderness. 2. Bloody diarrhea. 3. At biopsy from the ileum: Trans-mural inflammation with hyper-trophic lymphoid follicles & several granulomas.



Ulcerative colitis 1. Pseudo-polyps. 2. Sclerosing cholangitis (pruritus, fatigue, ↑ alkaline phosphatase & beaded biliary tree on barium radio-graphy). 3. Bloody diarrhea causing iron deficiency anemia.

Deficiency of maltase in the brush border of small intestine results in ↑ passage of maltose in stool. ry

Hyper-tri-glyceridemia 2 to lipo-protein lipase deficiency is characterized by: 1. Attacks of pancreatitis. 2. Eruptive xanthomas. 3. ↑ plasma tri-glyceride tri-glyceride level (2000 mg/dL). 



Osmotic diarrhea stops when the patient stops taking food.

MISCELLANEOUS 

The gastro-colic reflex involves an ↑ in the motility of the colon in response to stretch in the stomach & by-products of digestion in the small intestine leading to defecation.



Defecation is facilitated by employing the Valsalva manoeuver.



Omeprazole is a proton pump inhibitor that blocks H /K ATPase.



Vaso-active intestinal peptide dilates GI resistance vessels.



↓ body temperature ↓ BMR.



Gastric emptying can occur without brain-stem co-ordination.



+

+

Segmentation is the motility pattern primarily responsible for the propulsion of chyme along the small intestine.


Mahmoud Shoaib

76

NEUROLOGY DISEASES 



A patient with mitral valve disease & atrial fibrillation is most likely to have a mural thrombus in the left atrium predisposing to a massive stroke in the left middle cerebral artery & death (thrombo-embolism).

Confusion is a recognized side effect of pre-frontal leucotomy (= lobotomy).

A cerebral abscess is characterized by: 1. Headache & fever. 2. Ring enhancing mass in CT. 3. At biopsy: gliosis, f ibrosis, necrosis, neutro-phils & lympho-cytes. 





1. 2. 3. 4.

A diffuse cerebral edema is most severe in the white matter of the brain. Cerebral edema with uncal herniation is characterized by: Headache. Papilledema. Death. At autopsy: recent hemorrhages in the pons.

Herpes simplex virus (HSV) meningitis is characterized by: 1. Confusion or seizure. lympho-cytes +/- RBCs. 2. Normal CSF analysis except there is ↑ lympho-cytes 3. Hemorrhagic lesions of the temporal lobe (characteristic). 



1. 2. 3.  





1. 2. 3. 4. 5.

Vestibular neuron-itis (inflammation of the vestibular division of the 8 th C.N.) is characterized by: Abrupt onset of dizziness with nausea & vomiting. Headache. Nystagmus towards the affected side. These symptoms would dis-appear in 7-10 days. Cerebellar tremor is a slow, broad tremor of the extremities that occurs at the end of a purposeful (directed or voluntary) movement (intention tremor) & may be accompanied by dys-arthria, nystagmus, gait problems & postural tremor of the trunk & neck. In Parkinsonism, the 1ry area involved is substantia nigra. ac ute, auto-immune poly-radiculo-pathy which Guillain-Barre syndrome (GBS) is an acute, affects the peripheral nervous system & is characterized by: An acute infection (e.g. URTI) within the past 1-4 weeks. Ascending paralysis (weakness in the legs that spreads to the upper limbs & face). Complete loss of deep tendon reflexes. Normal CSF analysis except there is ↑ lympho-cytes lympho-cytes & protein. Gradual recovery after 4 weeks.


Mahmoud Shoaib

77

UMNL o o o o

o

1. 2. 3. 4. 5.

Spasticity. Clasp-knife response. No muscle wasting. Brisk (exaggerated) tendon jerk (stretch) reflex (e.g. knee jerk). Babinski sign +ve (the big toe is raised rather than curled downwards).

Site of the lesion Dominant Broca's area. Lateral geniculate nucleus of the thalamus. Supra-chiasmatic nucleus of the hypothalamus. Ventro-medial nucleus of the hypothalamus. Pons.

LMNL o

Hypo-tonia.

o

Muscle wasting.

 

Affected function Motor aphasia. Vision.



Circadian rhythm.



Satiety & female sexual drive.



6. Reticular activating system.



7. Gracile nucleus.



8. Cuneate nucleus.



9. Fasiculus cuneatus (the lateral portion of the dorsal column). ry 10. 1 sensory tri-geminal nucleus.





11. Posterior column-medial lemniscus.



12. Lateral spino-thalamic tract.



13. Anterior spino-thalamic tract.









Rapid eye movement (REM) sleep. Events occurring during this phase include penile erections, night mares & hypo-tonia except in ocular muscles. Level of awakeness. Fine touch, vibration & proprioception in the lower part of the body (below T6). Fine touch, vibration & proprioception in the upper part of the body (above T6). Fine touch, vibration & proprioception in the ipsi-lateral arm. Fine touch, vibration & proprioception in the face & ear. Fine touch. Contra-lateral loss of pain & temperature below the level of the lesion. Contra-lateral loss of crude touch & pressure sensation below the level of the lesion.

A stroke affecting the thalamus causes hyper-esthesia. Large injury to the non-dominant parietal cortex (e.g. right posterior parietal cortex) may cause the patient to ignore the serous nature of his illness & to neglect or even deny the presence of the paralysis affecting the side of the body opposite to the lesion.

In myasthenia gravis, the response of skeletal muscle to nerve stimulation is weakened.


Mahmoud Shoaib

78









Horner's syndrome (uni-lateral loss of sympathetic innervation of the face) is characterized by ipsi-lateral ptosis, miosis & an-hydrosis (red & dry skin due to loss of vaso-dilatation & sweating). Fixation of the ossicles due to fibrosis causes depressed hearing when tested by air conduction but normal bone conduction. Hyper-opia (far sightedness) can be corrected with convex glasses. Glaucoma is not a rare cause of blindness in the UK. anti-muscarinics (pilocarpine) or ββEmergency treatment of acute angle glaucoma is by anti-muscarinics blockers (timolol) to dilate the pupils. Carbonic anhydrase inhibitors can also be used but they are not useful for long-term treatment.

Lesion 1. Inter-collicular brain stem transection. 2. Complete transection of the spinal cord at T6. 3. Brown-sequard syndrome (hemi-section of the spinal cord).

Effect o

De-cerebrate rigidity.

o

Areflexia in the immediate post-injury period.

1. Ipsi-lateral spastic paralysis (cortico-spinal tract). 2. Ipsi-lateral loss of vibration & proprioception (position sense) (fasiculus gracilis or cuneatus). 3. Contra-lateral loss of pain & temperature sensation beginning 1-2 segments below the lesion (spinothalamic tract). 



There is also ipsi-lateral loss of all sensory modalities & flaccid paralysis at the level of the lesion.

A neural tube defect (e.g. open spina bifida & anencephaly) is characterized by ↑ AFP.

HEMORRHAGES Epi-dural hematoma (EDH) is characterized by: 1. A lucid interval (a period of alertness of about 30 minutes followed by unconsciousness). 2. On CT brain: a convex, lens-shaped area of hemorrhage. 

Sub-dural hemorrhage (SDH) occurs due to damage of the dural bridging vein. It is characterized by: 1. Headache, irritability & strange behavior. 2. On CT brain: a concave area of hemorrhage. 

Spontaneous sub-arachnoid hemorrhage (SAH) is mostly due to ruptured berry aneurysm & is characterized by: 1. Headache. 2. Sudden loss of consciousness. 


Mahmoud Shoaib

79

TUMORS 









Meningioma is among the most common intra-cranial tumors. It is the only brain tumor that is more common in women. Schwannoma has the best prognosis following surgery among the intra-cranial neoplasms. Glioblastoma multiforme (grade 4 astro-cytoma) presents as a large poorly demarcated mass with central necrosis. ry It is the most common & aggressive type of 1 brain tumor (52%). Well differentiated astro-cytoma is the most common type of astro-cytomas. It expresses giant fibrillary acidic protein (GFAP) which possibly functions as a tumor suppressor & is a useful diagnostic marker in a tissue biopsy. Metastases are typically located at the grey-white junction. They mostly originate in the lung, skin, kidney, breast & colon.

CSF in health & disease  

o o o

It is actively secreted by the choroid plexus. It is drained into the venous system by the arachnoid granulations.

Volume: 150 ml. Formation: 500 ml/day. pH: < arterial blood.

1. Pressure



Normal 50-180 mmH 2o (8-15 mmHg).

2. WBCs



< 5/ml (2/3 lympho-cytes & 1/3 mono-cytes).

3. Glucose 4. Protein

 

50-100 mg/dl (2/3 of plasma value). 20-40 mg/dl (0.2-0.4 gm/L) (0.3% of plasma value).

o

o

o o

Bacterial meningitis > 180 mmH2o. > 10 with neutronphil predominance. < 40 mg/dl. > 4.5 mg/dl.

MISCELLANEOUS



Pre-central gyrus is the 1 ry motor cortex. ry Post-central gyrus is the 1 sensory cortex.



In EEG, α waves have a frequency wave of 8-12 Hz.



Dopamine is the neuro-transmitter of the nigro-striatal pathway.



Substance P has been associated in the regulation of: 1. Pain. 2. Mood disorders, anxiety & stress. 


Mahmoud Shoaib

80

3. Neuro-genesis. 4. It is as a potent vaso-dilator. 















Pacinian corpuscle is depolarized by mechanical distortion & is in-dependent of K channels.

+

Phentolamine is an α-adrenergic receptor blocker causing pupil constriction. The introduction of cold water in one ear may cause giddiness & nausea due to convection currents in endo-lymph. A sudden ↑ in the pitch of a voice causes the location of maximal basilar membrane displacement to move toward the base of the cochlea.

The dark current of retinal photo-receptors is generated by non-selective cation channels. A sudden loud sound is more likely to damage the cochlea than a loud sound that develops slowly because there is a latent period before the attenuation reflex can occur (40-80 ms). During far accommodation, the ciliary muscles are relaxed. During periods of silent counting, regional cerebral blood flow (rCBF) ( rCBF) ↑ within the supplementary motor area.



γ-motor neurons are inhibited by descending motor tracts.



In the vestibular labyrinth, the utricle senses motion in the horizontal plane.



Presbycusis is characterized by loss of sensitivity to high-frequency sounds.


Mahmoud Shoaib

81

ENDOCRINOLOGY PITUITARY GLAND 

1. 2. 3. 4.

Hyper-prolactinemia (e.g. pituitary adenoma) is characterized by: Absence of menstrual periods. Milk production from breasts. Headache. Lost temporal vision (bi-temporal hemianopia). Sheehan's syndrome (pituitary necrosis or post-partum hypo-pituitarism) occurs due to postpartum hemorrhage.



In diabetes insipidus, blood volume is maintained at near normal levels because water intake is appropriately adjusted.



+

A patient with syndrome of in-appropriate ADH secretion (SIADH) has a low serum Na due to the dilutional effect of ADH-induced water retention in the collecting tubules.



THYROID & PARA-THYROID GLANDS Tertiary (hypo-thalamic-pituitary axis) hypo-thyroidism hypo-thyroidism is characterized by: 1. Hypo-thalamic failure. 

1

Hypo-thyroidism (↑ TSH , ↓ T3 resin uptake, T 3 & T4 e.g. Grave's disease or after total thyroidectomy) is characterized by: 1. Lethargy. 2. Peri-orbital swelling. 



1. 2. 3. 4. 



Sub-acute granulomatous (De-Quervain's) thyroiditis is characterized by: An influenza virus infection of the lung preceding the lesion. Hyper-thyroidism at the time of initial presentation. An enlarged painful thyroid. The course of the disease can run for only 3 months. Chronic lympho-cytic (Hashimoto's) thyroiditis is the most common cause of hypothyroidism in areas of the world where iodine levels are sufficient. It is characterized by a high titre of anti-thyro-globulin anti-thyro-globulin & anti-micro-somal Abs. 2+

After thyroidectomy, serum Ca is requested in the early post-operative period to help management of problems associated with hypo-calcemia due to hypo-para-thyroidism.

A thyro-glossal cyst is characterized by: 1. A mass in the mid-line of the neck between the isthmus of the thyroid & the hyoid bone. 2. Upward movement with protrusion of the to ngue. 3. On aspiration, a clear mucoid fluid. 

1

Also in endemic goiter.


Mahmoud Shoaib

82



1. 2. 3. 4.

Hyper-para-thyroidism (↑ PTH) (e.g. PTH) (e.g. para-thyroid adenoma) is characterized by: Stones (nephro-lithiasis). Bones (bone pain). Abdominal groans (peptic ulcer disease or pancreatitis). Psychic moans (depression). 2+

3-

5. ↑ Ca & ↓ Po4 . 1 6. ↑ calciterol (the active form of vitamin D = 1,25-di-hydroxy-chole-calciferol ). 

ry

CRF (e.g. in a diabetic patient) causes 2 hyper-para-thyroidism with osteo-malacia & spontaneous bone fractures.

ADRENAL GLAND 

1. 2. 3. 4. 5.

Conn syndrome (↑ mineralo-corticoid mineralo-corticoid hormone, aldosterone) is characterized by: + Na & water retention. Hypertension. Muscle cramps, headache & metabolic alkalosis. + ↓ K concentration. ↓ serum renin ( renin ( –ve –ve feedback).

Cushing's syndrome (e.g. long term steroid therapy or adreno-cortical carcinoma) is characterized by: 1. Increasing weakness. 2. Hyper-tension. 3. Purple striae on the trunk. 

Addison's disease (e.g. chronic 1 ry adrenal insufficiency or adrenalectomised subject) is characterized by: 1. Progressive weakness & easy fatigability. 2. Anorexia, nausea, vomiting, weight loss & diarrhea. 3. Hyper-kalemia. 

4. 5. 6. 7. 

Hypo-glycemia between meals. Hypo-natremia. Hypo-tension. ↑ skin pigmentation.

Abrupt dis-continuation of cortico-steroid therapy without tapering the dose is i s the most common cause of Addisonian crisis (acute adrenal failure).

Waterhouse-Fridrichsen syndrome is characterized by: 1. Acute infection, usually meningo-coccal. 2. Acute adreno-cortical insufficiency. 



Congenital adrenal hyper-plasia occurs due to deficiency of 21-hydroxylase that is involved with the bio-synthesis of steroid hormones.

1

Its formation is ↑ with ↑ PTH levels. It is ↓ in patients with rickets due to vitamin D deficiency.


Mahmoud Shoaib

83

HORMONES & RECEPTORS 

The intra-cellular domain of insulin receptors has tyrosine kinase activity.



Steroid hormones act via gene transcription.



Stimulation of either β1 or β2 receptors activates adenylate cyclase.

MISCELLANEOUS 













A patient with blood glucose level of 200 mg/dl & -ve dipstick test for urinary glucose has significantly ↓ GFR.

The Cori cycle deals with conversion of glucose to lactate & vice versa. The basic patho-physiology of diabetic keto-acidosis is insulin insufficiency. It is characterized by ↓ plasma C-peptide levels. The hypo-thalamic hypo-physeal venous portal system carries prolactin-inhibitory hormone from the hypo-thalamus to the anterior pituitary. In the absence of this hormone, prolactin secretion ↑.

ACTH stimulates the conversion of cholesterol to pregnenolone to promote the production of cortisol & adrenal androgens. Pro-opio-melano-cortin (POMC) is the precursor hormone for ACTH which exhibits diurnal rhythm in its secretion. The effects of hormones on liver glycogen content: Catecholamines Gluco-corticoids ↓ ↑

Hormone 1. Growth hormone 2. Glucagon 1

3. Insulin

Induction of secretion o Exercise. o ↓ blood glucose. o ↓ blood glucose. o ↑ blood amino acids. o o

↑ blood glucose. ↑ blood amino acids.

4. FSH

5. ADH (vasopressin) 2



    

o o

↑ plasma osmolarity. ↓ plasma volume.

6. Thyroxin

  

Glucagon ↓ Effects ↑ blood glucose (↑ hepatic glycoglycogenolysis & Gluco -neo-genesis). ↑ lipo-lysis. lipo-lysis. ↓ blood amino acids. ↓ lipo-lysis. lipo-lysis. ↓ proteo-lysis. proteo-lysis. Synthesis of androgen-binding protein (in men). ↓ urine volume. ↓ gastric blood flow. Depletes fat stores.

1

Its secretion is inhibited by α2-adrenergic agonists (e.g. somato-statin, sympathetic nervous stimulation & adrenaline). 2 In its presence, the glomerular filtrate will be iso-tonic to plasma in the cortical collecting tubule.


Mahmoud Shoaib

84

7. PTH

o

o

8. Aldosterone (secreted from zona glomerulosa) 9. Cortisol

o

↓ extra-cellular extra-cellular 2+ ionized Ca . 3↑ plasma Po 4 . ↑ renin & angiotensin 1 II .









10.Cate-cholamines 10.Cate-cholamines

1



3-

↑ loss of Po 4 in the urine.

+

Re-absorption of Na in distal tubules, saliva, sweat & stool.

↑ normal sensitivity of vascular smooth muscle to the vasoconstrictor effects of catecholamines. ↓ phago-cytosis phago-cytosis by WBCs. Glyco-geno-lysis in live & muscle cells increasing blood glucose.

ry

e.g. severe de-hydration causes 2 hyper-aldosteronism.


Mahmoud Shoaib

85

MALE RE-PRODUCTIVE SYSTEM











LH (of pituitary baso-phils) It is a glycol-protein hormone that stimulates the inter-stitial (leydig) cells in the testes to secrete testosterone.

Testosterone is synthesized from cholesterol & is converted to di-hydro-testosterone by 5-α 5-α-reductase. In plasma, 2% of testosterone circulates as free testosterone. It stimulates bone marrow. Sertoli cells produce the hormone inhibin & androgen binding protein which is regulated by FSH. 2+

Activation of spermatozoa is a Ca -dependent event. Capacitation occurs in the uterus allowing enhanced motility. Semen:

Part 1. The seminal vesicles 2. The ampulla of the vas 3. The prostate 



FSH It stimulates spermato-genesis spermato-genesis (↑ sperm count).

  

Secretion Large amounts of ascorbic acid. Fructose. Citric acid & acid phosphatase.

Normal sperm count = 200-500 million/ejaculate.

TESTIS 

Hypo-gonadism due to deficiency of GnRH is termed Kallman's syndrome.



Removal of the testes ↑ GnRH secretion.



Infertility of the male can be explained by failure of the testis to descend (cryptorchidism).

PENIS 



Balanitis is inflammation of the glans penis. The most common causative agent is staphylo-coccus aureus. Phimosis is a medical condition in which the fore-skin of the penis of an uncircumscribed male cannot be fully retracted.

Peyronie's disease is characterized by: 1. Painful erection. 2. Deviation of the penis when it is erect. 



Hypo-spadias is a birth defect in which there is an abnormal opening of the urethra onto the ventral surface of the penis.


Mahmoud Shoaib

86

DISEASES 







Spermato-cele presents as a painless, trans-illuminant swelling at the upper pole of the testis. Varico-cele presents by a painless, twisted mass along the spermatic s permatic cord which is more prominent when the patient stands & feels like a bag of worms. Dark field micro-scopic examination of exudate or secretions is the best test for ry diagnosing 1 syphilis. BPH is treated by finasteride which is a 5-α 5-α-reductase inhibitor (anti-androgen).


Mahmoud Shoaib

87

FEMALE RE-PRODUCTIVE SYSTEM & BREAST In the menstrual cycle: 1. 17β-estradiol 17β-estradiol measures typically < 50 ng/ml at menstruation, rises with follicular development reaching a peak (surge) before ovulation, drop briefly at ovulation & rise nd again during the luteal phase for a 2 peak. 2. The secretory stage is characterized by highly coiled arteries with edema in endometrial biopsy. 3. Menstruation occurs after the demise of corpus luteum in the ovary. 

In the ovarian cycle: 1. Formation of Graafian follicles is a feature of the antral phase. 

st

In the 1 trimester, there is: 1. ↑ CO. 2. ↑ alveolar ventilation ventilation.. 3. ↑ RPF. RPF. 











1. 2. 3. 4. 5.



nd

In the 2 trimester, there is ↓ pCo2. In pregnancy, RBC volume ↑ but this frequently lags behind the plasma volume, resulting in ↓ hematocrit & Hb concentration (physiological anemia of pregnancy). Administration of an Ab that neutralizes hCG for 7 days starting 4 weeks after conception causes death of the embryo & its subsequent expulsion.

FSH secretion ↑ after menopause. Progesterone: It is an absolute requirement for maintenance of pregnancy. Menstrual bleeding is a consequent of its withdrawal. st It is produced by the corpus luteum during the 1 2 weeks of pregnancy then from the syncytio-tropho-blast tissue of the fetal placenta. It stimulates respiration & ↓ pCo2. Its ↑ concentrations blocks the action of prolactin so lactation does not occur during pregnancy. Deficiency of progesterone is associated with habitual abortion.

Estrogens: 1. They are produced from androgens. 2. ↑ circulating level of coagulation factors 2, 7, 9 & 10. 







Human placental lactogen (hPL) is a placental hormone that is similar in structure & function to growth hormone. Oxytocin produces contraction of the smooth muscle cells underlying the milkproducing alveolar cells. Prolactin prevents the menstrual cycle during the early post-partum period (↓ gonado-trophins).


Mahmoud Shoaib

88

Labor: 1. Maternal Pgs is the most important factor for initiation of labor. 2. Estrogen stimulates the number of oxytocin receptors in the decidua & myo-metrium. 





Hot flush (night sweat) is a symptom of changing hormone levels considered characteristic of menopause. Glucose is transported by facilitated diffusion across the placental barrier.

DISEASES 





The geno-type of a complete hydatidi-form mole is 46 XX (90%) or 46 XY (10%) & i s completely paternal in origin. 75-80% of post-partum hemorrhages are due to uterine atony which is characterized by severe vaginal bleeding.

Acute fatty live of pregnancy is a rare life-threatening complication of pregnancy that rd occurs in the 3 trimester or the immediate period after delivery.



Following bilateral oophorectomy, there is ↓ fat deposition.



Intra-hepatic cholestasis of pregnancy causes marked pruritus.



Endo-metriosis causes dys-pareunia.



Imperforate hymen is most likely to be associated with hemato-colpos.

BREAST 





Virginal breast hyper-trophy (juvenile macro-mastia or giganto-mastia) causes excessive growth of the breast during puberty. Hepatic failure causes bi-lateral gyneco-mastia. Acute mastitis usually occurs 2-3 weeks after delivery but it can occur at any time. The nipple becomes cracked or fissured with nursing. Typical causative organisms include staphylo-coccus aureus, strepto-coccus species & Escherichia coli.



Oral contra-ceptive use is most likely associated with breast cyst formation.



A woman with a leaking silicone breast implant is at an ↑ risk of pain & contracture.


Mahmoud Shoaib

89

PATHOLOGY, MICRO-BIOLOGY & PHARMACOLOGY


Mahmoud Shoaib

90

CELL INJURY & WOUND HEALING 1. Hyper-trophy

o

2. Hyper-plasia

3. Atrophy

o o o

4. Apoptosis

o

o

It is a feature of cerebral infarction due to high lipid content.

o

1. 2. 6. Coagulative necrosis 7. Liquefactive necrosis 8. Meta-plasia

o

o o

1. 2. 3.  







Uterine growth during pregnancy is an example of concomitant hyper-plasia & hyper-trophy. ↓ cell size (early). size (early). ↓ cell number (late). ↑ number of auto-phagic auto-phagic vacuoles. e.g. immobilization of a broken limb in a plaster cast. Single cell necrosis (micro-scopic): Cell shrinkage. Chromatin condensation. Formation of cyto-plasmic blebs & apoptotic bodies. Phago-cytosis of apoptotic cells or cell bodies. It is a feature of: Breast trauma. Acute pancreatitis (enzymatic fat necrosis causing hypo-calcemia). It is accompanied by disruption of the cell membrane.

o

1. 2. 3. 4.

5. Fat necrosis

↑ cell size & its contents. E.g. a heart of a patient with long-standing HTN & aortic stenosis. E.g. During pregnancy, the breast shows lobular hyper-plasia allowing the mother to nurse her infant for a long time.

The reversible substitution of one adult ti ssue type (epithelial or mesenchymal) normally found at a site for another. It is an adaptive response. Examples: In habitual smokers, the respiratory epithelium shows stratified squamous meta-plasia. In GERD, the esophageal epithelium shows columnar meta-plasia (columnar epithelium with goblet cells). Myo-sitis ossificans. It is most likely to occur with vitamin A deficiency.

A severe soft-tissue injury following a RTA causes mobilization of fat stores. A man working in a power plant (exposed to radio-active materials) suffers radiation injury due to free radical formation. Free radical injury also causes sunburn on the cheeks (redness & pain) after spending a sunny day on the beach.

Lipo-chrome (lipo-fuscin = age) pigment from wear & tear accumulates in the myocardial fibers with age causing a small heart with a dark brown color on section. The tanning of skin (dark skin complexion) is achieved by melano-cytes having the enzyme tyrosinase to oxidize tyrosine to di-hydroxy-phenyl-alanine in the pathway for melanin production.


Mahmoud Shoaib

91

Wet gangrene occurs in case of small intestinal infarction following sudden & total occlusion of mesenteric arterial blood flow. The splenic flexure is at greatest risk because it is the watershed between the distribution of the superior & inferior mesenteric arteries.



The liver is most likely to suffer severe damage after exposure to carbon tetra-chloride used in dry cleaning facilities, either on the skin or by inhalation.



ATP depletion associated with hypoxic & chemical (toxic) injury causes ↑ un-folded un-folded protein response.





1. 2. 3. 4. 5. 











1

Wound healing: Almost all of the tensile strength that can be obtained is achieved within 3 months. Malignancy is not a a complication of wound healing. Vitamin A deficiency is not likely likely to influence wound healing. Presence of sutures aids wound healing. Tyrosine kinase functions intra-cellularly in cells involved in wound healing. Hyaline degeneration is characterized by homogenous, ground-glass, pink-staining appearance of cells. Hamartoma is an abnormal amount & arrangement of normal tissue that is appropriate or normal for the area in which the tissue arises. Organization of the hematoma is infiltration of its periphery by new capillaries, fibroblasts & collagen (the same composition of granulation tissue)1. Diapedesis is the passage of WBCs through the blood vessel wall. The time required for a scar of a small myo-cardial infarct to reach full strength is several months.

Chemical burns may be aggravated by the use of neutralizing agents.

Fibro-blast growth factor stimulates angio-genesis, wound repair, development & hemato-poiesis.


Mahmoud Shoaib

92

INFLAMMATION & IMMUNOLOGY 























The main step in the mechanism of cell injury in case of hemo-lytic anemia after taking an over-the-counter analgesic is the formation of IgG/IgM Abs. After a bee sting, a patient develops a raised, red, swollen lesion at the site of injury due to vaso-dilation. The functions of ICAM 1 (inter-cellular adhesion molecule 1) & VCAM 1 (V for vascular) in inflammation is leuco-cyte adhesion.

The skin test response in allergy is most likely to be the result of releasing histamine from mast cells. The receptor-platelet-derived growth factor complex activates tyrosine kinase to signal the cell to divide. Pg & bradykinin production is associated with pain (e.g. acute appendicitis). Clearance of strepto-coccus pneumoniae from the lung parenchyma is accomplished through generation of hydrogen peroxide by the major inflammatory cell type responding to this infection. Inter-stitial lung disease caused by inhaling silica dust for many years is attributed to release of growth factors by macro-phages. Acute inflammation of the throat (e.g. sore throat) is characterized by the presence of a pharyngeal purulent exudate. Recurrent bacterial infections suggest a lack of B -cell immune function (e.g. X-linked agamma-globulinemia). Tissue typing before a renal transplant ↓ CD4 lympho-cyte activation. Ciclo-sporin is an immune-suppressant immune-suppressant drug that binds to a cyto-solic protein (cyclophilin) of immune-competent lympho-cytes.



Bone marrow is the origin of the mono-nuclear phago-cyte system.



Blockage of 5-lipoxygenase 5-lipoxygenase inhibits the synthesis of leuko-trienes.



HLA-B27 is associated with post-gono-coccal arthritis.

REJECTION

o o o

Hyper-acute Complement-mediated. Within minutes. Not reversed.

o o o

Acute Cell-mediated. 11-14 days. Reversed by antilymphocyte globulin.


o o o

Chronic Poorly under-stood. Several months-years. Not reversed.

Mahmoud Shoaib

93

HYPER-SENSITIVITY Type I (immediate – (immediate – allergy allergy & anaphylaxis due to histamine release) Type II (complement-mediated)

o o o o o o o

o o o o

Type III Type IV (delayed – (delayed – cell-mediated cell-mediated by CD4, CD8 & macro-phages)

o o

Drug allergy (e.g. penicillin). Food allergy. Parasitic infestations (e.g. liver flukes). Auto-immune hemo-lytic anemia. Pernicious anemia. Transfusion reactions. Hemo-lytic disease of the new-born (erythro1 blastosis fetalis) "Rh in-compatibility" . Immune thrombo-cyto-penia. Hashimoto's thyroiditis. Grave's disease. Myasthenia gravis. Dust inhalation. Tuberculosis.

GRAFTS 1. Iso-graft (syn-graft) 2. Auto-graft

o

o

3. Allo-graft

o

4. Xeno-graft

o

Between genetically identical individuals (i.e. identical twins). Between 2 parts of the body of the same individual. Between 2 members of the same species (i.e. 2 humans). Between 2 members of 2 species (e.g. baboon to human).

o

o

o

Rejection does not occur. Rejection is likely. Rejection is highly likely.

CYTO-KINES 1. IL-1

o o

2. IL-5 3. IL-6 4. IL-7 5. IL-10 6. γ-interferon 7. TNF

1

o o o

o o o

It ↑ the expression of adhesion factors on endothelial cells. It is an endogenous pyrogen. It is a major regulator of esino-philic accumulation in tissues. It is secreted by T-cells, macro-phages, muscles & osteo-blasts. It is involved in B-cell, T-cell & NK cell survival, development & homeo-stasis. It has anti-inflammatory properties. It is produced by T-cells & induces MHC II proteins. It is an appetite suppressant.

IM administration of anti-Rh Ab (Rh immune-globulin) to the mother protects the baby.


Mahmoud Shoaib

94

NEO-PLASIA 



















Un-controlled (autonomous) growth would best distinguish a lesion as a neo-plasm rather than a granuloma. Well-defined encapsulation of a lesion tends to point towards a benign neo-plasm rather than a malignant one. Cyto-keratin stain of inter-mediate filaments within cells is useful for confirmation that a neo-plasm is a carcinoma (i.e. of epithelial origin) , however, cells found to be vimentin +ve are of mesenchymal origin (e.g. osteo-sarcoma). Invasion is the micro-scopic finding which indicates that the neo-plasm is malignant. It is also the feature that is taken into account when staging a cancer. c ommon para-neo-plastic syndrome caused by ↑ level of Hyper-calcemia is the most common PTH-related protein.

Lipo-sarcoma is the most common soft tissue sarcoma & is radio-resistant. Tumors of the skin, lung, breast, prostate & colon are more likely to occur in adults than in children. Skin cancer, ano-genital cancer, non-Hodgkin's lymphoma & Kaposi sarcoma are the most common cancers in organ trans-plant recipients. The malignant potential of renal adeno-carcinoma & carcinoid tumors is most often associated with tumor size. In new-borns, the sacro-coccygeal area most commonly gives rise to tumors derived from all 3 germ-cell layers.

THE MOST COMMON



Papillary carcinoma The appendix Meta-plastic polyp Osteo-chondroma (exostosis)



Dermoid cyst (benign cystic teratoma)

  

o o o o

o

ry

1 malignant thyroid tumor. Gut carcinoid tumors. Colo-rectal lesion of epithelial derivation. Benign bone tumor affecting individuals under the age of 21 years. Benign germ cell tumor of the ovaries in the pre-meno-pausal women.

PRE-MALIGNANT LESIONS

   

Lesion Solar (senile or actinic) keratosis Erythro-plasia. Barrett's esophagus due to GERD. Cervical dys-plasia.

Cancer o o o

SCC. Carcinoma of the oral cavity. Esoghageal adeno-carcinoma.

o


Mahmoud Shoaib

95

CARCINO-GENS Substance  





Arsenic. Asbestos (in ship-building & insulation industries). Smoking (nitrosamine, 2-naphthyl amine, …). P53 is a tumor-suppressor gene.

o o

o

Tumor Hepatic angio-sarcoma. Meso-thelioma (most common malignant pleural tumor). Bladder cancer.

TUMOR MARKERS

    

Tumor marker BRCA 1 & 2 genes CA-27.29 CEA CA-125 Calcitonin

Tumor o

o o o

Breast. Pancreas. Ovary. Medullary carcinoma.

CANCER ONCO-GENES Onco-gene     

Erb B3. C-abl. N-myc. C-myc. Ras.

Tumor o o o o o

Breast. CML. Neuro-blastoma. Burkitt's lymphoma. Colon.

PARA-NEO-PLASTIC SYNDROMES

  

 

Para-neo-plastic syndrome Dermato-myo-sitis. Acanthosis nigricans. Trousseau's superficial migratory thrombo-phlebitis. Pure RBC aplasia. ↑ ADH & ACTH.

o o o

o o

Tumor Breast carcinoma. Gastric carcinoma. Pancreatic carcinoma. Thymoma. Small-cell carcinoma of the lung.

TUMOR-CHROMO-SOME ASSOCIATION Chromo-some    

1. 11. 13. 17.

o o o o


Tumor Neuro-blastoma. Wilm's tumor. Retino-blastoma. Neuro-fibroma & osteo-genic sarcoma.

Mahmoud Shoaib

96

SITE-SPECIFIC TUMORS SKIN TNM staging of SCC: ry 1 tumor (T) o Tx: minimum requirements to ry assess 1 tumor cannot be met. 

Tis: pre-invasive cancer (carcinoma in situ). ry o T0: no evidence of 1 tumor. o T1: tumor ≤ 2 cm in its greatest dimension. o T2: tumor 2-4 cm. o T3: tumor > 5 cm. o T4: tumor with extension to bone, muscle, skin, antrum, neck, …

Regional LNs (N) o Tx: minimum requirements to assess the regional LNs cannot be met.

o

N0: no evidence of regional LN involvement. o N1: movable homo-lateral regional LNs. o N2: movable contra-lateral or bi-lateral regional LNs. o N3: fixed regional LNs. o

Distant metastases (M) o Tx: minimum requirements to the presence of distant metastasis cannot be met. M0: no evidence of distant metastases. o M1: evidence of distant metastases. o



Marjolin's ulcer is a carcinoma that develops in a scar & is painless.



Xero-derma pigmentosum is characterized by defective DNA repair.

BONE 

1. 2. 3. 4. 5. 6. 

1. 2. 3. 4.

Ewing's sarcoma (small round blue cell tumor) is characterized by: Boys. Young age (10-15 years). A mass in the diaphysis of long bones (especially the femur & flat bones of the pelvis) with overlying cortical erosion & soft tissue extension. The affected site is frequently tender, warm & swollen. The characteristic peri-osteal reaction produces layers of reactive bone deposited in an onion-skin fashion. At biopsy: numerous small round blue cells. Osteo-sarcoma is characterized by: Osteoid production. Tumors usually arise in the meta-physis of the long bones of the extremities (almost 60% occur around the knee). It is associated with Paget's disease of bone (osteitis deformans). On X-ray, it shows the classic sign of Codman's triangle.


Mahmoud Shoaib

97

LUNGS  

The lung is the most common site for metastatic neoplasms. Pulmonary metastases are the most common neoplasms involving the lung.

Small-cell (oat-cell) anaplastic carcinoma is characterized by: 1. Chronic cough, weight loss & hemoptysis. 2. Para-neoplastic syndromes e.g. 1) SIADH. 2) Ectopic ACTH secretion (trunk obesity, easy bruising & osteo-prosis). 3) Lambert-Eaton myasthenic syndrome. 3. Disseminated disease at the time of initial presentation. 

ry

TNM staging for 1 lung cancer: ry 1 tumor o Tx: +ve malignant cytology results, no lesion seen. o T1: diameter ≤ 3 cm. o T2: diameter > 3 cm. o T3: extension to pleura, chest wall, diaphragm, peri-cardium, within 2 cm of carina or total atelectasis. o T4: invasion of mediastinal organs (e.g. esophagus, trachea, great vessels or heart), malignant pleural effusion or satellite ry nodules within the 1 lobe. 

LNs o N0: no LNs involved. o N1: ipsi-lateral broncho-pulmonary or hilar LNs. o N2: ipsi-lateral mediastinal or sub-carinal LNs. o N3: contra-lateral mediastinal or hilar, or any supra-clavicular LNs.

Bronchial carcinoid is characterized by: 1. Localized bronchiectasis. 2. Ectopic secretion of ACTH, growth hormone or gastrin hormone. 

Squamous cell carcinoma is characterized by: 1. A cavitary lesion in a proximal bronchus. 2. Keratinization in the form of squamous pearls or individual cells with markedly esinophilic (pink) dense cyto-plasm. 





Pulmonary hamartoma is the most common benign tumor of the lung. The patient is usually healthy, asymptomatic & non-smoker. Broncho-alveolar carcinoma is a distinct sub-type of adeno-carcinoma which classically manifests on chest X-ray as an inter-stitial lung disease , a solitary peripheral nodule, as a multi-focal disease or as a rapidly progressive pneumonic form. It arises from type II pneumo-cytes. Patients with advanced disease present with voluminous watery discharge.


Mahmoud Shoaib

98

GIT, LIVER, GALL-BLADDER & PANCREAS 

A hyper-plastic rectal polyp has no tendency to turn malignant.



Familial poly-posis coli has 100% risk of carcinoma within 30 years of diagnosis.



Hamartomatous polyps in the colon are a feature of Peutz-Jeghers syndrome.



Caecal adeno-carcinoma is associated with a K-ras mutation in the neo-plastic cells.



1. 2. 3. 4.

5-year survival rate after surgical resection of colon cancer: Stage (Duke's stage). 5-year survival rate o I (A). > 90%. II (B). 70-85%. o o III (C). 30-60%. IV (D). 5%. o

1. 2. 3. 4.

Hepato-cellular carcinoma is characterized by: Aflatoxin exposure. An enlarged liver with ascites. Right hypo-chondrial pain. ↑ serum levels of AFP.



The 5-year survival rate of gall-bladder carcinoma is 1% despite s urgical intervention.



The 5-year survival rate of infiltrating ductal adeno-carcinoma of the pancreas is < 5%.



URINARY TRACT 

Wilm's tumor (nephro-blastoma) results from chromosomal deletion of WT1 (Wilm's tumor suppressor gene) on chromosome 11. Its most common presentation is a painless palpable abdominal mass. It is most likely to be found in a 5-year-old child.

The lack of findings in the bladder (-ve cysto-scopy) but the presence of atypical cells in urinalysis specimen suggests that the lesion is located higher up, possibly in the renal pelvis or ureter e.g. transitional cell carcinoma of renal pelvis which is characterized also by: 1. Long history of smoking. 2. A multi-centric origin. 

Renal cell carcinoma is characterized by: 1. Long history of smoking. 2. Intermittent hematuria & costo-vertebral pain. 3. Poly-cythemia, hyper-calcemia & eosino-philia. 



o o

TNM staging of renal cell carcinoma: Stage 1: tumors ≤ 7 cm & confined to the kidney. Stage 2: tumors > 7 cm but still confined to the kidney.


Mahmoud Shoaib

99

o

o



o o

o o o o

Stage 3: tumors extending into the renal vein or vena cava, involving the ipsi-lateral adrenal gland &/or peri-nephric fat, or which have spread to local LNs. Stage 4: tumors extending beyond Gerota's fascia, to > 1 local LN, or with distant metastasis. TNM staging of bladder cancer: CIS: carcinoma in situ, high-grade dys-plasia, confined to the epithelium. Ta: papillary tumor confined to the epithelium. T1: invasion into the lamina propria. T2: invasion into the muscularis propria. T3: invasion into the peri-vesical fat. T4: invasion into adjacent organs (e.g. prostate, rectum, side wall of the pelvis, …).

NERVOUS SYSTEM 













Meningioma is among the most common intra-cranial tumors. It is the only brain tumor that is more common in women. Schwannoma has the best prognosis following surgery among the intra-cranial neoplasms. Glioblastoma multiforme (grade 4 astro-cytoma) presents as a large poorly demarcated mass with central necrosis. ry It is the most common & aggressive type of 1 brain tumor (52%). Well differentiated astro-cytoma is the most common type of astro-cytomas. It expresses giant fibrillary acidic protein (GFAP) which possibly functions as a tumor suppressor & is a useful diagnostic marker in a tissue biopsy. Metastases are typically located at the grey-white junction. They mostly originate in the lung, skin, kidney, breast & colon. In children, medullo-blastoma (neuro-blastoma or granulo-balstoma) usually ori ginates in the region of the cerebellar vermis.

Neuro-fibroma arises from the CT of the nerve sheath.

LEUKEMIAS, LYMPHOMAS & MULTIPLE MYELOMA

1. 2. 3. 4. 5.

AML ↓ RBCs. ↓ platelets. ↑ WBCs. Blasts with Auer rods. Splenomegaly.

1. 2. 3. 4.

CLL ↓ RBCs. ↓ platelets. ↑ WBCs. Numerous small mature lymphocytes.

CML 1. ↑ WBCs (e.g. 3 100.000/mm ). 2. ↓ LAP (leucocyte alkaline phosphatase).

Leukemoid reaction 1. ↑ WBCs (e.g. 3 50.000/mm ). 2. ↑ LAP.

Hodgkin's lymphoma is characterized by: 1. Low-grade fever, night sweats & malaise. 


Mahmoud Shoaib

100

2. Non-tender cervical & supra-cervical lymph-adenopathy with Reed-Sternberg cells. 



1. 2. 3. 4. 5. 6.

Burkitt's lymphoma (a type of non-Hodgkin's lymphoma associated with EBV) presents with enlarged lower jaw, blast cells & macro-phages. Multiple myeloma is characterized by: Bone pain. Renal insufficiency. Hyper-calcemia. +ve semi-quantitative sulpho-salicylic acid test for urine protein (Bence Jones protein). -ve urine dipstick dipstick testing for protein as it is most sensitive for albumin, not globulins. Bone marrow biopsy shows numerous plasma cells.

MULTIPLE ENDO-CRINE NEO-PLASIA (MEN) MEN type I (3 p) 1. Para-thyroid. 2. Pituitary. 3. Pancreatic islet cells.

MEN type II 1. Para-thyroid (hyper-para-thyroidism). 2. Pheo-chromo-cytoma. 3. Medullary carcinoma of the thyroid.

PITUITARY GLAND 

A cranio-pharyngioma is a supra-sellar neoplasm with calcifications that is eroding the bone of the surrounding sella turcica. It usually affects children between the ages of 5-10 years causing headache.

PAROTID GLAND Pleo-morphic adenoma (mixed tumor) of the parotid gland is the most common benign parotid tumor followed by Warthin's tumor. It is characterized by: 1. Epithelial & myo-epithelial cells forming acini, tubules & ducts. 2. Myxoid & chondroid stroma. 3. Local recurrence after enucleation. 

THYROID & PARA-THYROID GLANDS

1. 2. 3. 4.

Papillary carcinoma is characterized by: History of exposure to ionizing radiation in childhood. Psammoma bodies in a histological section. The best prognosis among all thyroid carcinomas. It is treated by total thyroidectomy with preservation of the para-thyroid glands.



US is a useful investigation for distinguishing cystic from solid lesions.




Mahmoud Shoaib

101

ADRENAL GLAND 

1. 2. 3. 4.

Pheo-chromo-cytoma is characterized by: Hypertensive attacks precipitated by emotional stress. Anxiety. A retro-peritoneal right-sided abdominal mass. ↓ plasma concentration of insulin.

5. ↑ serum nor-adrenaline nor-adrenaline levels. 6. ↑ urinary meta-nephrine, meta-nephrine, vanillyl-mandelic acid (VMA) & homo-valinic acid.

TESTIS 

1. 2. 3. 4. 5.

Germ cell tumors: Seminoma (40%) (very radio-sensitive). Embryonal carcinoma (25%). Teratoma (5%) (it is characterized by an enlarged testis – testis – on on section, there are elements similar to skin & its appendages). Terato-carcinoma (25%). Chorio-carcinoma (1%).

TNM staging of seminoma: ry 1 tumor o Ts: intra-tubular germ cell neoplasia (carcinoma in situ). o T1: tumor limited to testis/epididymis – testis/epididymis – invasion invasion of the tunica albunginea. o T2: vascular or lymphatic invasion – invasion – invasion of the tunica vaginalis. o T3: invasion of the spermatic cord. o T4: invasion of the scrotum. 



LNs o N0: no regional LN metastases. o N1: LNs ≤ 2 cm. o N2: LNs 2-5 cm. o N3: LNs ≥ 5 cm.

Serum tumor marker o S0: normal. o S1: LDH < 1.5 times the reference, β-hCG β-hCG < 5000 mIU/ml & AFP < 1000 ng/ml. o S2: LDH 1.5-10 times the reference, β-hCG β-hCG 5000-50.000 mIU/ml & AFP 1000-10.000 ng/ml. o S3: LDH > 10 times the reference, β-hCG β-hCG > 50.000 mIU/ml & AFP > 10.000 ng/ml.

NSGCTs have a poorer prognosis than seminomas.

Prostatic adeno-carcinoma is characterized by: 1. An enlarged prostate with a nodular feel. 2. ↑ serum levels of PSA (it functions to liquefy gelatinous semen after ejaculation). 3. Spread through the internal vertebral venous plexus. 



o o o o o o o

ry

TNM classification of the 1 tumor of the penis: Tx: cannot be assessed. T0: not evident. Tis: carcinoma in situ. Ta: non-invasive verrucous carcinoma. T1: invasion of the sub-epithelial CT. T2: invasion of the corpora spongiosum or cavernosum. T3: invasion of the urethra or prostate.


Mahmoud Shoaib

102

o



T4: invasion of the adjacent structures. Sertoli-leyding tumor (arrheno-blastoma) is a hormone-producing tumor that secretes testosterone.

FEMALE RE-PRODUCTIVE SYSTEM 







1. 2. 3.  

1. 2. 3. 4. 

Kiss cancer of the labium majus is an example of spread of malignant tumors by implantation. Cervical intra-epithelial neo-plasia (CIN) is most strongly associated with HPV infection. The most reliable & easy method to confirm the diagnosis of cervical carcinoma is PAP (cervical) smear.

Chorio-carcinoma is preceded by: Hydatidi-form mole (50%). Abortion of ectopic pregnancy (20%). Normal term pregnancy (20-30%). It is characterized by progressive ↑ in β-hCG β-hCG levels. Poly-cystic ovary (Stein Leventhal) syndrome (PCO) is characterized by: Lack of regular ovulation. Excessive amount or effects of androgenic hormones. Hirsutism. Enlarged ovaries. Fibro-thecoma is a benign ovarian tumor that is most likely to be associated with endometrial hyper-plasia.

Micro-glandular hyper-plasia is characterized by: 1. Long term contra-ceptive use. 2. Abnormal vaginal bleeding. 3. An endo-cervical poly-poid mass. 

Ovarian serous cyst-adeno-carcinoma is characterized by: 1. Ascites. 2. Uni-locular cystic tumor. 3. Clusters of malignant epithelial cells surrounding Psammoma bodies. 


Mahmoud Shoaib

103

BREAST 

Fibro-adenoma of the breast is characterized by a firm, rubbery, mobile mass with no palpable axillary LNs.



Phyllodes tumor is characterized by a stromal & an epithelial components.



A bloody nipple discharge is most likely to be due to intra-ductal papilloma.

Paget's disease of the nipple is characterized by: 1. Affection of one nipple with redness, oozing & crusting. 2. At section: large cells at the dermal-epi-dermal junction that stain positively for mucin. 



A lobular carcinoma in situ of the breast indicates that the opposite breast might also be involved.

Medullary carcinoma of the breast is characterized by: 1. A soft fleshy mass. 2. At section: lymphoid stroma with little fibrosis surrounding sheets of large vesicular cells. 



A breast carcinoma with axillary LN metastases would suggest a poor prognosis.


Mahmoud Shoaib

104

MICRO-BIOLOGY 



The virulence of bacteria is related to toxin & enzyme production. Endo-toxins cause fever, hypo-tension, erythema & neck stiffness s tiffness (e.g. meningitis caused by Neisseria meningitides).

Exo-toxin production is the mechanism for patho-genesis in: 1. Pseudomonas infection. 2. Diphtheria infection. 

Staphylo-coccus aureus causes: 1. Folliculitis which is inflammation of ≥  hair follicles. follicles . 2. Infective endo-carditis in IV drug abusers. 3. Meningitis where gram staining of CSF reveals gram +ve cocci in grape -like clusters. It is assumed to be a β-lactamase-producing β -lactamase-producing organism until the laboratory reports its anti-biotic sensitivity & the drug of choice will be methi-cillin as it is also bactericidal & is not associated with toxicity. 









1. 2. 3. 4. 







It produces coagulase which is used for its identification in the laboratory as this enzyme causes clotting of plasma (formation of fibrin).

Strepto-coccus viridans is the most likely causative agent for infective endo-carditis. Endo-carditis with staphylo-coccus aureus is most likely to be associated with a mycotic aneurysm. Escherichia coli with pilli cause the vast majority of cases of bacterial pyelo-nephritis & cystitis (after catheter introduction into the urethra). Escherichia coli septicemia is characterized by: Delirium, confusion & un-co-operation. o High grade fever (> 39 C). Hypo-tension, tachy-cardia & tachypnea. Urinary WBCs > 200/HPF. Lacto-bacillus is a gram +ve facultative bacteria present in the vagina & GIT. It produces lactic acid making its environment acidic. The outer membrane is found in gram – gram –ve ve but not in gram +ve bacteria. Bacteroides fragilis is a gram – gram –ve ve obligate an-aerobe bacillus of the gut. It is involved in 90% of an-aerobic potential infections. Cholera toxin continually stimulates adenylate cyclase to over-produce cAMP by catalyzing the binding of ADP-ribose t Gs protein.



Clostridium botulinum causes fetal food poisoning (botulism).



The Widal test is a serological test for Salmonella typhi.



The respiratory tract is the most common portal of entry in Blastomyces dermatidis.


Mahmoud Shoaib

105



Brucellosis (un-dulant or Malta fever) is transmitted by un-pasteurized milk.



An abscess containing sulphur granules is a feature of action-mycosis.



Greenish pus ear discharge is characteristic of pseudomonas aeruginosa.













Crypto-sporidium parvum infection is a protozoal infection that causes an acute diarrhea in immune-compromised patients (e.g. AIDS). Steven-Johnson syndrome (erythema multi-forme major) is a recognized serious side effect of sulphonamides. When a child is bitten by a stray dog, the physician should immediately start rabies vaccine & give anti-rabies serum.

UV light is used as an anti-microbial physical agent because it causes the formation of pyrimidine dimers. The most likely reason for varicella-zoster infection in a patient receiving cancer chemotherapy is T-cell deficiency.

Povidone-iodine is active against spore-forming organisms.


Mahmoud Shoaib

106

PHARMACOLOGY ANTI-BIOTICS



Drug Meropenem



Ciprofloxacin (quinolone) "drug of choice" Doxycycline



Amikacin





Di-cloxacillin (penicillin) Tri-methoprim Tazobactam st Pipera-cillin "1 choice" Azlo-cillin "2 nd choice" Oral vanco-mycin.



Linezolid



  











Erythro-mycin (macrolide antibiotic) Fusidic acid

Uses o Meningitis & pneumonia. o Pulmonary anthrax.

Prostatitis, sinusitis, syphilis & chlamydia infections. o Pneumonia caused by pseudo-monas aeruginosa. o Folliculitis. o

o

UTIs.









 

o

Inhibition of bacterial DNA replication & transcription. Inhibition of protein synthesis by preventing the amino-acyl tRNA from binding to the A site of the ribo-some. Inhibition of protein synthesis by binding to the 30S sub-unit of the ribosome.

Inhibition of di-hydro-folate reductase. Inhibition of β-lactamase. β-lactamase.

Pneumonia caused by pseudo-monas aeruginosa.

Clostridium difficile infection. o MRSA. o Methi-cillin-resistant staphylo-coccus aureus. o







o

Mechanism of action Inhibition of bacterial wall synthesis.

Staphylo-coccus aureus wound infection.



Inhibition of initiation of bacterial protein synthesis. Inhibition of trans-location of peptides.

Inhibition of the trans-location of elongation factor G from ribo-some.

rd

Ceftriaxone (3 generation cephalosporin) Genta-mycin

o

Gram – Gram –ve ve sepsis.




S/E: disturbed hearing & loss of balance.

Mahmoud Shoaib

107

NAUSEA, VOMITING, DIARRHEA & CONSTIPATION



     

Drug Ondasetron Di-phenoxy-late Loperamide Methyl-cellulose Psyllium Metoclopramide Docusate sodium

Uses o Chemo-therapyinduced vomiting. o Non-infective diarrhea. o

Chronic constipation & diverticulosis.

Nausea & vomiting. o Constipation & hemorrhoids. o







 

Mechanism of action Serotonin antagonist. Opiate agonist slowing down intestinal contractions. Holds water in the stool. Dopamine antagonist Lowers the surface tension of the stool facilitating penetration of water & fats.

ANALGESICS



Drug Sufentanil



Tramadol

Uses o Pain relief for a short period of time. o Pain relief.



Morphine

o

Analgesic of choice in acute myo-cardial infarction.





Mechanism of action Opiate agonist. Modulation of GABAergic. Noradrenergic & serotonergic systems.



ASPIRIN (ACETYL SALICYLIC ACID) 





It ↓ thromboxane A2 formation in platelets producing inhibition of platelet aggregation. Warfarin dose must be ↓ if taken simultaneously with aspirin. It ↓ pain by ↓ the production of Pgs & thromboxanes through non-competitive & irreversible inhibition of COX enzyme. It exerts a protective effect against colon cancer.

ANTI-FUNGAL DRUGS

  

Drug Ketoconazole Griseofulvin Fluconazole

Mechanism of action o Inhibition of the fungal ergosterol synthesis. o

Inhibition of cyto-chrome p450.


Mahmoud Shoaib

108

ANTI-ULCER DRUGS

 

Drug Cimetidine Lansoprazole

Mechanism of action Competitive inhibition of H2 receptors. + + Irreversible inhibition of H /K ATPase.

 

CHEMO-THERAPEUTIC AGENTS

   

Drug Etoposide Vincristine Cisplatin Tamoxifen

Uses o Lung cancer. o Hodgkin's lymphoma. o Small-cell lung cancer. o Chemo-prevention in breast cancer.

Mechanism of action   

S/E: peripheral neuro-pathy. Cross-linking of DNA. It causes breast epithelial cells to rest in G0 phase.

CHEMO-THERAPY REGIMENS (ACRONYMS)

 



Cancer Colo-rectal Hodgkin's lymphoma Non-Hodgkin's lymphoma

 



Regimen 1 FOLFOX (FOL= 5-fluro-uracil – 5-fluro-uracil – F= Folinic acid – OX= oxaliplatin). ABVD (Adria-mycin – dria-mycin – Bleo-mycin – leo-mycin – Vinblastine - Dacarbazine). CHOP (Cyclo-phosphamide – yclo-phosphamide – Hydroxy-rubicin – ydroxy-rubicin – Oncovin (vincristine) - Prednisone).

MISCELLANEOUS



Drug Atorvastatin



Sodium nitroprusside infusion Desmopressin



Abciximab



Strepto-kinase



Carbachol



Mexiletine



Uses o After coronary artery bypass surgery. o After repair of an AAA.

Mild hemo-philia A & thrombo-cyto-penia which occurs after a prolonged surgery on cardiopulmonary by-pass. o Prevention of re-stenosis after angio-plasty. o Myo-cardial infarction & pulmonary embolism. o Open-angle glaucoma & during cataract surgery. o

o



Mechanism of action Inhibits cholesterol synthesis.



Vaso-dilator.









It induces the release of stored factor 8 & von Willebrand factor.

Inhibition of platelet aggregation. It is usually given once because of the risk of allergic reaction. It is a para-sympatho-mimetic para-sympatho-mimetic that causes miosis & ↑ flow of aqueous humor.

Ventricular arrhythmias.

1

It is used as an Adjuvant chemo-therapy for colo-rectal carcinoma as it enhances the effect of 5fluro-uracil.


Mahmoud Shoaib

109



Buspirone Spironolactone



Mithra-mycin



   



Methimazole Propyl-thio-uracil Cyclo-phosphamide Methotrexate

 

o

Hyper-calcemia of malignancy. 



o

Anxio-lytic. + Potassium-sparing diuretic (↑ Na + excretion & ↓ K excretion).

Crohn's disease.



Inhibition of the addition of iodide to thyro-globulin. S/E: urinary bladder cancer. Inhibition of T-cell activation.

Nadolol is poorly lipid-soluble.


Mahmoud Shoaib

110

GENERAL COLLECTIONS


Mahmoud Shoaib

111

TUBERCULOSIS 

1.

2. 3.  



1ry tuberculosis is characterized by: Sub-pleural nodule, predominantly in the lower lung, usually in one site 1. The granuloma (tubercle) is characterized by the presence of central caseous (caseation) necrosis (cheesy white material) enclosed within a distinctive inflammatory border of mono-nuclear giant cells, lympho-cytes & plasma cells. Enlarged regional (e.g. hilar or mediastinal) LNs. Sputum sample contains acid-fast bacilli with +ve Mantoux test. Initial therapy is Rifampicin + isoniazid (or streptomycin) + pyrazinamide + ethambutol. Tuberculosis of the lumbar spine with a cold abscess tracks along the psoas major muscle to the groin. Tuberculous trophic ulcer is usually found over the ball of the big toe.

ANTI-TUBERCULOSIS DRUGS

  



Drug Rifampicin Ethambutol Isoniazid

Mechanism of action o Inhibition of DNA-dependent RNA poly-merase. o Inhibition of the formation of the bacterial cell wall. o Inhibition of mycolic acid synthesis in the bacterial cell wall.

In tuberculosis, those patient contacts who have a +ve skin test but no other signs of disease should receive prophylactic isoniazid.

LYMPHATICS 1. Tip of the tongue 2. Ovary 3. Scrotum/labia majora & anus. 4. Lower part of the vagina & anal canal, dorsum of the foot, big toe & penile urethra. 5. Anal canal

1

 





Sub-mental LNs. Lateral & pre-aortic LNs (located at the origin of the ovarian arteries). Superficial inguinal LNs (vertical group in case of acute paronychia involving the big toe).

Internal iliac LNs.

ry

The 1 lesion (Gohn focus) is located in the lower part of the upper lobe or the upper part of the lower lobe.


Mahmoud Shoaib

Tmp_21700-Basic Science Summary for the MRCS-2069613412

Recommend Documents