20587313 Biology Form5 Locomotion and Support

Biology form5 Chapter 2 : Locomotion and support 2.1 Support and Locomotion in Humans and Animals 2.2 Appreciating Appreciating a Healthy Musculoskeleta Musculoskeletall System System 2.3 Support in Plants

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2.1 Support and Locomotion in Humans and Animals

Skeleton Exoskeleton

Endoskeleton

-enclosed the bodies of arthropods (insects and crabs) -supports the important internal organs and protects the internal structures from damage -thin and flexible at joints -on a process called ecdysis, the insects shed their skeleton to increase in size

-found in all vertebrates -consists of internal fluids in -hardbskeleton of bones are the confined body cavity made up of phosphate and -the fluid is held under calcium pressure in compartments surrounded by muscles -important to maintain the body shape, supports the soft -maintains the shape of softbody tissues and protects the bodied organisms,such as internal organs from getting hydra sp, earthworm and sea injured anemones -certain parts of endoskeleton stores minerals

Human Skeleton

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Hydrostatic

Locomotion

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Human Skeleton Axial Skeleton Appendicular Skeleton _____________ The structure of a joint How movement is brought in a limb The structure of a muscle Consequences of impaired musculoskeleton [email protected] system on support and locomotion

Human Skeleton 

Axial Skeleton Skull

Vertebral column

Thoracic

The part of the skeleton that forms an imaginary line down the back of the body is known as axial skeleton. The bones that make up the axial skeleton are the skull, the vertebral column (cervical vertebrae, thoracic vertebrae, lumbar vertebrae, sacrum and coccyx), sternum and ribs.

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Human Skeleton 


Vertebral column

-contains 22 bones -protects the brain (carnial bones) -provides support for the entrance of the respiratory and digestive systems (facial bones) -Suture (immovable joints that hold the bone which makes up the skull firmly )

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Thoracic

Human Skeleton 


Vertebral column

Thoracic 1

The vertebral column is a series of small bones that forms a flexible structure and provides support. It runs down the dorsal side of a vertebrate animal. Each bone is known as a vertebra.

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Human Skeleton 


Vertebral column

Thoracic

Cervical - composed of seven vertebrae and forming the neck. Thoracic - composed of twelve vertebrae and joining to the ribcage together forming the thorax. Lumbar – composed of five vertebrae. These are the biggest in size. Sacrum – composed of five fused vertebrae in adults. They may occur as separate bones in young children. They join with the hip bone forming the pelvis. Coccyx – formed from the fusion of two or four vertebrae. Sometimes known as the tail bone. [email protected]

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Human Skeleton 


Vertebral column

Thoracic 1 2 3 4

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Human Skeleton 


Vertebral column

Thoracic 1 2 3 4

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Human Skeleton 


Vertebral column

Thoracic 1 2 3 4

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Human Skeleton 


Vertebral column

Thoracic -protects the heart and lungs -12 pairs of ribs make up the sides of the thoracic cavity -they articulate with the twelve vertebrae of the thoracic region

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Human Skeleton 

Appendicular Skeleton

The bones that make up the appendicular skeleton are scapula, clavicle or collar bone, humerus, radius, ulna, tibia, femur, pelvic girdle and fibula. Scapula - flat, triangular-shaped bone, that forms the skeletal basis of the shoulder. Humerus – the bone of the upper arm, its upper end articulates with the scapula to form a ball-end-socket joint at the shoulder, allowing movement in all directions. Ulna – longer bone of the forearm that articulates with the humerus. Radius – flattened, slightly curved bone in the hand. Pelvic girdle – provides connection between the axial skeleton and the hind limbs. Femur – largest bone in the human body, its lower end articulates with the tibia to form a hinge joint at the knee. Fibula – shorter and smaller bone, found along with the tibia, giving skeletal support to the leg. [email protected]

The structure of a joint

-cartilage (reduces friction is a shock absorber, cushions the joint, protects the bones from wearing away) -synovial fluid (acts as a lubicant, minimises the friction between the [email protected] ends of the bones)


-allow the bones to rotate in all directions -allow the swinging of arms and legs in a circular motion -example:the hip joint between ferum and the pelvic girdle, the shoulder joint between the humerus and the pectoral [email protected] girdle.


-Also called knee joints -found in the elbows, and phalanges of toes and fingers -allow the lower leg to swing back and forth -allow the movement of bones in one plate [email protected] -work like a hinge on a door

How movement is brought in a limb Tendon-tough, strong and inelastic strands of dense connective tissues -connects skeletal muscle to the bones Ligaments-holds the bones together -tough sheets of elastic fibres -connects bone to bone -allows the movements and prevent the dislocation of the joint during movement Antagonistic pairs-a pair of muscles work together to allow coordinated movement of skeletal joints.( contracts & relaxes) The movement of the forelimb is brought about by the contraction and relaxation of a pair of antagonistic muscles, namely the biceps and the triceps. The arm is flexed by the contraction of the bicep muscles. The tricep muscles relax as the bicep muscles become thicker and shorter. Contraction of the bicep muscles pulls the ulna up thus bending the arm at the elbow joint. To straighten the arm, the tricep muscles contract while the bicep muscles relax. Contraction of the tricep muscles pulls the ulna down and arm is straightened. [email protected]

The structure of a muscle 1

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Skeleton muscle (such as biceps consists of bundles of muscle fibres and a large supply of nerves and blood vessels.)

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Muscle fibre (a single, long cylindrical cell that contains many nuclei)

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Myofibril (bundles of smaller units made muscle fibre, made up of two types of protein)

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Actin & myosin (interaction of both proteins cause muscle contraction)

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Consequences of impaired musculoskeleton system on support and locomotion osteoporosis

Muscular dystrophy

Arthritis

Osteoporosis is a disease where the bone tissue starts eroding, making the bones brittle and prone to fractures. T is common in the elderly and women after menopause. Osteoporosis can be prevented by taking a diet rich in calcium, phosphorus and vitamin D, regular weight-bearing exercise, and avoiding smoking and excessive alcohol.

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Muscular dystrophy

Arthritis

It is a genetic disorder of the muscle tissues caused by the lack of nourishment to the affected muscles. It causes the muscles in the body to become very weak. The muscles break down and are replaced with fatty deposits over time. Muscular dystrophy is more common in males than in females. It is usually seen in children between two to ten years old. Duchenne muscular dystrophy is the most common form of muscular dystrophy, caused by an X-linked recessive gene. Treatment-There is no known treatment, medicine, or surgery to cure muscular dystrophy or stop the muscles from weakening. The goal of treatment is to prevent deformity and allow the child to function as independently as possible. [email protected]


Muscular dystrophy

Arthritis

Arthritis is the inflammation of one or more joints characterised by swelling, warmth, redness of the overlying area, pain and restriction of movement. Is comprises more than 100 distinct conditions and can affect people at any stage of life. The most common forms are osteoarthritis, rheumatoid arthritis and gout. Osteoarthristis is most common in older people where the top layer of cartilage breaks down and wears away. Rheumatoid arthritis causes inflammation of the synovial membrane of the joints in the hands, wrists, neck, jaw, elbows, feet and ankles, which may cause damage to the cartilage and bone itself. Gout is condition that results from deposition of uric acid in the joints.

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Locomotion Earthworm Grasshopper Fish Bird Frog [email protected]

Earthworm -Invertebrate which do not have exoskeleton, but uses body fluid to maintain a hydrostatic skeleton. -The movement of the earthworm is aided by hydrostatic pressure so that the body of the earthworm can shorten, elongate and protrudes forward. -there are two pairs of muscle i.e. circular and longitudinal muscles that act antagonistically. -contraction and retraction of circular and longitudinal muscle will cause a peristalsis wave and enables it to move forward.

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Earthworm

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Grasshopper Grasshoppers have an exoskeleton. Muscle bundles on the inside, are attached to the exoskeleton. Across the joints. The muscles work in that antagonistic pairs is known as the flexor and extensor muscles. The contraction results in the bending of the joint and the relaxation results in the extending of the joint. Antagonistic pairs allow movement of the appendage in both the directions. Grasshoppers have three pairs of legs. The body is supported on a tripod of three legs in walking. The other three legs pull or push the body forwards. The third pair legs are long with powerful muscles for jumping. The extensor muscles are attached to the tendons. Before jumping, the rear legs are fully flexed. Energy is stored in the elastic tendons caused by the contraction of both the flexor and the extensor muscles. During jumping, the flexor muscles relax and the extensor contract causing the rear legs to straighten. The energy stored in the tendon propels the grasshopper into the air. The grasshopper can jump 20 times its body length. Grasshoppers have a pair of wings. The wings are flattened extensions of the exoskeleton. During flight, the wings of the grasshopper move forwards and backwards, upwards and downwards through the air owing to contractions of the flight muscles. This produces a lift by driving the air downwards which in turn enables the grasshopper to lift off and fly. [email protected]

Fish Fish have a streamlined body, smooth and rounded at the anterior part of the fish, and long and tapering body towards the posterior end. This helps to overcome water resistance while moving in water. Fish swim by contracting and relaxing a succession of muscle blocks called myotomes. These muscle contract and relax alternately on each side of the body, starting at the head and progressing down towards the tail. The alternate contracting and relaxing of myotomes, which bends part of the body first towards the other side, result in a series of waves travelling down the fish’s body. The rear part of each wave thrusts against the water and propels the fish forward. Fish have fins to overcome the instability in water while swimming. The dorsal and the ventral fins are useful in stabilising the fish as it swims, helping to change direction quickly, or used with the other fins for applying brakes. Paired pectoral and pelvic fins help to overcome rolling and pitching by stabilising the fish’s body.

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Bird The bird’s wing has a curved shape called an aerofoil. The air on the upper part has a lower pressure than the air moving over the lower part. This pressure difference makes the lifting of the body possible by the wing. There are two pairs of antagonistic muscles that are evolved for flight. The larger pair called the pectoralis major contracts for the downstroke. The pectoralis minor handles the upstroke, which needs far less power. Conversely, the contraction of the pectoralis major muscles moves the wing [email protected] downwards and backwards.

Frog Frogs make use of their long hind legs to effect several kinds of locomotion such as jumping, hopping, swimming, burrowing, and climbing. The long hind legs have well developed muscles to lift them off the ground. When the frogs are at rest, the long hind legs are folded into a ‘Z’ shape. Frogs crawl by extending and retracting their fore and hind limbs. During hopping, the extensor muscles contract rapidly, causing the hind legs to straighten suddenly. A force is produced to push the frog upwards and forwards. Frogs land on their short forelimbs. The short forelimbs absorb the shock of impact. Most frogs can jump ten times their body length.

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Frog

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2.2 Appreciating a Healthy Musculoskeletal System

-A balanced diet - It is very important to have a diet rich in proteins to build muscles and calcium for strong teeth and bones. Fats and oils should be avoided. -Good posture – A good posture is to be maintained in all occasions and slouching should be avoided. A good posture while perfoming certain tasks helps to ensure that the body is always well-supported. -Proper attire for daily activities – Comfortable clothes and shoes should be worn especially during long walks so that the flow of movement is not hindered. -Exercise – The right amount and the right kind of exercise are very important for a healthy musculoskeletal system. The correct and safe exercise technique should be practised. The wrong kind of exercise can cause serious injuries to the musculoskeletal system. Appropriate precautions should be taken during vigorous activities which can result in strains, sprains, dislocations and fractures.

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2.3 Support in Plants -To allow growth towards sunlight in order for photosynthesis to take place -To allow leaves be placed in proper position for maximum absorption of light -To allow flowers be placed in a position that they can attract insects for pollination -To allow fruits be placed in strategic places for effective dispersal of seeds

Terrestrial plants

Aguatic plants Test

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Aguatic plants Submerged Plants

Floating plants

-Possesses features to help them stay afloat on water -The natural buoyancy of the water helps the aquatic plants to float -Consists of spongy tissue filled with air sacs which are known as aerenchyma tissues. These tissues help the leaves and stems of the aquatic plants to float on the surface of the water Air sacs

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Aguatic plants Submerged Plants

Floating plants

-Floating plant will float because of the stem and leave which consists of parenchyma cells that has a lot of air spaces. -The air is less compressed compared with the water hence making it float. -The roots are fibrous and spreads in the water surface so as to prevent them being carried away by the water flow and hold them in place by surface tension. -when there is growth in the middle of the roots, growth of roots is straight downwards so that they are more stable. -the leaves and shoots are waterproof so that water do not seep into the cells causing damage. Eichhornia sp.

Lotus

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Terrestrial plants Herbaceous plant

Woody plants

They depend on the turgidity of the cells and other supportive tissues for support. Parenchyma tissues store starch, sugars and water. These cells maintain the turgidity of the plants to give support to the plant. Collenchyma tissues support young and herbaceous plants. These cells have slightly thickened walls of cellulose which give support to the leaf or flower stalk and young stems.

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Special


Woody plants

Special

-supported by sclerenchyma and xylem tissues -Sclerenchyma tissues are composed of cell with secondary cell walls that are usually usually lignified -Have thick, rigid and non-stretchable cell walls -support the non-growing parts of plants -divide into 2 types of sclerenchyma tissues: fibres (long, thin and straight. Found outside the vascular bundles.) sclereids (short, small and irregular-shaped. Found in fruits and seeds)

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fibres

sclereids


Woody plants

During development ,the cell walls of the xylem vessels and tracheid are thickened with lignin which are deposited during plants secondary growth. There are different types of vessels.

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Special


Woody plants

Special

Special structural adaptations for external support in some terrestrial plants -roots come out from the lower part of the trunk and grow into the ground. -provide support for the trees. -roots are different from others. -important in breathing and growing

Tendrils

thorns

Twining stem Buttress root

Clasping root

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Test 1. What is the tisue represented in A? Collenchyma Parenchyma Sclerenchyma Epidermis 2. What is the tissue represented in B? Parenchyma Collenchymal Sclerenchyma Hyperdermis

3. What is the tissue enclosed in the oval labeled C? Phloem Xylem Fibers Parenchyma 4. What is the function of the tissue represented in D? Transport water Transport food Storage Photosynthesis What is the tissue represented in D? Parenchyma Chloroenchyma Collenchyma [email protected]

Hypodermis

20587313 Biology Form5 Locomotion and Support

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