HIGH YIELD EMBRYOLOGY EMBRYOLOGY General Embryology Hydatidiform mole Complete: no embryo, only trophoblast; abnormally high hCG; diploid, only paternal chromosomes Incomplete : partial embryo; high hCG; triploid with two sets of paternal chromosomes Choriocarcinoma : malignancy arising from invasive hydatidiform mole
most comm common on tumo tumorr in new newborn borns; s; aris arises es from from Sacrococcygeal Sacrococcygeal teratoma teratoma: most persistent primitive streak and contains tissues from all three germ layers Hemolytic Dieae of the !e"born #HD!$ or Erythroblatoi fetali : mother is Rh- and fetus is Rh+; mother produces antibody that results in hemolysis of fetal red cells Giving mother Rh immunoglobulin prevents !"# Head and !ec% Branchial apparat& Branchial clefts $grooves%: four pairs; ectoderm that forms only epithelium &st: e'ternal acoustic meatus nd ( - )th: usually regress but may unite to form cervical sinus that may form a branchial fistula Branchial pouches : four pairs; endoderm that forms only epithelium &st: auditory tube, mastoid antrum and tympanic cavity nd ( : palatine tonsil rd * : thymus and inferior parathyroid th ) : superior parathyroid and C cells of thyroid Branchial arches : five pairs; mesoderm that forms only skeletal muscle; ne&ral cret grows into each arch to give rise to all connective tissue elements $cartilage, bone and blood vessels% 'RCH
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M)SCLES uscles of mastication, anterior belly of digastric, mylohyoid, tensor tympani, tensor veli palatini uscles of facial e'pression, stapedius, posterior belly of digastric, stylohyoid .tylopharyngeus uscle uscles s of palate palate e'cept e'cept tensor tensor veli veli palati palatini, ni, phar pharyn ynge geal al musc muscle les, s, cric cricot othy hyro roid id usc uscle les s of lary laryn' n' e'ce e'cept pt cric cricot othy hyro roid id,, infer inferio ior r pharyngeal constrictor, cricopharyngeus, superior portion of esophagus
'rterie of branchial arche* ourth left: small part of arch of aorta ourth right: part one of subclavian artery .i'th left: ductus arteriosus, portion of pulmonary artery .i'th right: portion of pulmonary artery Cartilage of branchial arche* irst $eckel2s%: malleus, incus .econd $Reichert2s%: stapes, styloid process, lesser horn and superior portion of body of hyoid 0hird: greater horn and inferior portion of body of hyoid +hyrogloal d&ct cyt: located along the course that the thyroid migrated from the tongue to the neck Congenital torticolli: shortening of the sternocleidomastoid causing the chin to elevate to contralateral side; result of problems with birth $tearing or stretching of muscle% Cleft lip and cleft palate , a fa-orite COMLE. /&etion
General comments: although they often occur in association with each other, they are distinct; they are the result of very different processes and they occur at different times !e&ral cret is involved with both Cleft lip* failure of ma'illary prominence to 3oin paired $fused% medial nasal prominence $to form intermaxillary segment % Cleft palate* $&% 4nterior $to incisive foramen%: lateral palatine process $palatine shelf% fails to meet and fuse with primary palate; $(% 5osterior $to incisive foramen%: lateral palatine process does not meet or fuse with opposite side or with nasal septum; $*% Complete cleft: involves both primary and secondary palates Gatrointetinal Omphalocele: intestines do not return to abdominal cavity following their normal herniation; covered by amniotic sac /t may contain the liver as well as the intestinal tract /t is different from an umbilical hernia, which is covered by skin and connective tissue $rather than peritoneum and amnion% Congenital pyloric tenoi : pro3ectile vomiting is key feature; usually occurs during weeks ( 6 ) /t occurs most commonly in first-born males $&:&78% Hirchpr&ng0 dieae #aganglionic megacolon$ : #eural crest defect whereby cells fail to migrate into a portion of the hindgut resulting in a segment of bowel, which is noncontractile
Imperforate an&: anal membrane is thickened $from e'cessive growth of the genital fold% and does not perforate; more common in males than in females 9hen present, it is associated with intetinal atresia Mec%el0 di-ertic&l&m : outpocketing of distal ileum; portion of bowel that was continuous with the vitelline stalk and yolk sac 0his portion of the ileum is the central portion for the prea'ial and posta'ial limbs of intestinal rotation $a'is of rotation is superior mesenteric artery% 5resent on the antimesenteric wall $opposite the mesentery% about two feet from the ileocecal 3unction in an adult "iverticulum may present as a cyst, ligament, fistula or simple outpocketing; it often contains gastric tissue or pancreatic tissue R&le of 10 : ay be involved in case studies on C<1: 1= of population "iscovered by age of 1 yrs ocated appro' 1 ft from ileocecal 3unction 1> in length Contains 1 types of ectopic tissue $as stated above%
Cardio-ac&lar +etralogy of 2allot: classic four $?tetra>% associated problems include the following: $&% ventricular septal defect, $(% over-riding aorta $de'troposition of aorta%, $*% pulmonary stenosis, and $)% right ventricular hypertrophy )ndi-ided tr&nc& arterio& #peritent tr&nc& arterio&$ : neural crest defect whereby bulbar ridges fail to form 3atent d&ct& arterio& #3D'$ : common defect; associated with Rubella virus $German measles% and mother living in high altitudes during her pregnancy; fre@uency in females is ( 6 * 1 that in males; often seen with other heart defects 'trial eptal defect #'SD$ : very common; may involve first andAor second septa (entric&lar eptal defect #(SD$ : very common; invariably involves membranous portion of septum $rather than muscular part% +ranpoition of great arterie : most common cause of cyanosis in newborn; often seen with 4." andAor ." Coarctation of aorta : most commonly $B8=% constriction is 3u'taductal $opposite ductus arteriosus%; more common in males $(1% and often associated with bicuspid aortic valve Retroeophageal right &bcla-ian artery: fairly common; forms vascular ring around trachea and esophagus, but usually no problem clinically; forms as variation involving right seventh intersegmental artery
!er-o& ytem
epididymis, ductus deferens, seminal vesicle, e3aculatory duct epoophoron, paroophoron, Gartner2s duct
Paramesonephric (Mullerian) duct: Male* 2emale*
appendi' of testis and prostatic utricle uterine tube, uterus, and superior part of vagina
Horehoe %idney: inferior poles of both contact each other and fuse; ascent is checked by inferior mesenteric artery
Epipadia: rare; seen with e'strophy of urinary bladder Hypopadia: common; failure of urethral folds to completely meet; affects glans, midshaft or base of penis +&rner0 yndrome: )7 1, infantile female genitalia, ovarian streaks, and webbed neck 5linefelter0 yndrome : ) 11D; very common $&A788%; gynecomastia, infertile males Bicorn&ate &ter&: inferior portion of ullerian ducts fail to fuse resulting in two horns +etic&lar hydrocele: abdominal end of processus vaginalis does not completely seal allowing peritoneal $serous% fluid to drain to a persistent processus vaginalis Congenital ing&inal hernia: communication between peritoneal cavity and tunica vaginalis persists; intestines pass through deep inguinal ring and follow path of testicular descent 'ndrogen ineniti-ity yndrome: also known as testicular feminiEation; genetic male $)F 1D% but phenotypic female; testes are located in inguinal canal or in labia ma3ora; legally, medically and socially these people are females Change at Birth Umbilical arteries : Umbilical vein : Urachus: oramen ovale: !uctus arteriosus: !uctus venosus:
paired medial umbilical ligaments round ligament of the liver $unpaired% median umbilical ligament fossa ovalis ligamentum arteriosum ligamentum venosum
