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MAKTAB RENDAH SAINS MARA

PENGKALAN HULU,PERAK.

BIOLOGY NOTES(CHAPTER 2-4)

NAME:NURULAISYAH BT. ZAKARIA

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CLASS:504

COLLEGE NO. :08074

CHAPTER 2:

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LOCOMOTION ANDSUPPORT

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Form 5: Chapter 2 Locomotion and Support 2.1 Support and Locomotion in Humansand AnimalsChapter 2: Locomotion and Support2.1 Support and Locomotion in Humans andAnimals

Support System and Locomotion1. Provided by a skeleton

.2. Types of skeleton:

a) Exoskeleton shell- insects and crabs- importance:i) supports important body organs

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ii) protects the internal structures from damageiii) allows movementiv) waxy cuticles found on the surface of insects preventswaterloss.

b) Endoskeleton bones and cartilage- vertebrates- importance:

i) maintaining body shapeii) supporting soft tissueiii) protecting internal organs from injuryiv) stores mineral (calcium and phosphorus)v) produce blood cellsc) Hydrostatic skeleton internal watery fluids held under

pressure contained withinconfined spaces in the body surrounded by themuscles.- caterpillar and earthworm.

The human skeleton1. Parts:a) axial skeleton

b) appendicular skeletonThe axial skeleton:

1.Consists ofa) skullb) vertebral columnc) the ribsd) sternum

2. Skull consist of:a) Cranial bones enclose and protect the brainb) Facial bones protect and provide support for the entrances to the digestive

systemand respiratory systemc) Suture immovable joints which securely hold bones that make up the skulld) Jaw movable joint

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3. Vertebral column (spine or backbone)

a) composed of vertebrae.b) encloses and protects the spinal cord.

c) supports the head

d) serves as a point of attachment for the ribs, pelvic girdle and the muscles of theback and neck.e) cervical, thoracic and lumbar are moveable.f) sacrum and coccyx are immovable.g) invertebral discs in the vertebrae permits movement of the vertebral columnandabsorb vertical shock.h) varies in size and shape.i) vertebral foramen encloses the spinal cords.

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4. Cervical vertebraea) Have transverse formaen through which blood vessels and nerve pass.

5. Thoracic vertebraa) Have spinous processes that are long directed downwards.b) Spinous and transverse processes serve as points of attachment of muscles

andligaments.

6. Lumbar vertebra:a) Largest and strongest.b) Have large centrums which bear the weight of the lower back.

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7. Thorax:a) thoracic cage (consists of ribs and the sternum)b) encloses and protects the organs in the thoracic cavity and upper abdominal cavity.

The appendicular skeleton1. Consists of

:a) Pectoral girdle clavicle and scapula

b) Humerus

upper arm, longest bonec) Ulnad) Radiuse) Carpals wristf) Metacarpals palm of the handg) Phalanges fingers and toefinger

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g) Pelvic girdle consists of two hip bones which provide strong and stablesupport for the vertebral column.h) Femur thigh bone, longest, heaviest and strongesti) Tibiaj) Fibula

k) Patella

kneecapl) Tarsals anklem) Metatarsals foot

The structure of a joint1. Joint a place where two or more bones meet.2. Ligaments Hold bones together and allow them to move3. Synovial joint:a) Joint that contains a cavity filled with fluid that allow free movement.b) 4 features joint capsule (joint enclosure, reinforced and strengthened withligaments)- lined with thin synovial membrane (inner surface of the capsule)- secretes

synovial fluid lubricant which reduces friction between the ends of

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the bones)- covered with cartilage4. Cartilage cushions the joint, absorbs shock and reduces friction between the ends ofthe bones.5. Joints:-a) Hinge joint knee, elbow, finger and toe.- allows the leg to swing back and forth (oneplane).- 180 degreeb) Ball and socket joint rotational movement of bones in all directions.- shoulder and

hip joint.- 360 degree.

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How movement is brought about in a limb1. Skeletal muscle are responsible for voluntary movements of the body.

2. A muscle is attached to at least two bones across joints through tendons.3. Tendons are tough, strong and inelastic strands of dense connective tissues.4. Skeletal muscle produce movements by pulling on tendons attached to bones.5. A muscle can only pull6. It pulls when it contracts.7. A pair of muscle (antagonistic muscle) work together to allow coordinatedmovementof the skeletal joints.8. This means when one muscle contracts, the other muscle relaxes.9. Bending and straightening of the arm

a) When the biceps contract.b) The tendons transmit the pulling force produced by the contraction to theforearm.c) At the same time, the triceps relaxes.d) As a result, the elbow joint flexes or bends and the forearm moves upwards.e) This causes the bending and straightening of the arm.

The structure of a muscle1. A skeletal muscle such as the biceps consists of bundles of muscle fibresand largesupply of nerves and blood vessels.2. A muscle fibre is a single, long cylindrical cell that contains many nuclei.3. A muscle fibre is made up of bundles of smaller units called myofibrils.4. Each myofibril is made up of actin and myosin ( protein filaments).5. The interaction of both these proteins causes muscle contractions.6. Muscle contraction involves the nervous systema and requires energy.

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Consequences of impaired musculoskeletal system on support and locomotion1. Muscle crampDefinition: sudden contraction of one or more muscles which

results in a sudden, intense pain and inability to use the affected muscle.Causes: - common among endurance athletes.

- inadequate stretching and muscle fatigue.

2. Muscular dystrophyDefinition:Caused by the progressive degeneration and weakness of the skeletal musclesThatcontrol movement.Causes: - mutated gene which is found on the X chromosome and mainly affectsthe boys.

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3. OsteoporosisDefinition:Common bone disorder, especially among elderly women.

The bones becomethinner, more brittle and more porous.Causes:- Loss of bone mass begins after the age of 30 and accelerates greatly around theage

45.- If dietary intake of the of phosphate and calcium is insufficient.- Bone production and bone tissue will suffer resulting in brittle and fragile bones.

Symptoms:- fractures of the vertebrae, wrist or hips

- loss of height and stooped posture

Prevention:

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- Adequae intake of calcium, phosphorus and vitamin D.- Regular exercise

ArthritisDefinition:

- Decreased production of synovial fluid in joints and cartilage between bones becomethinner (osteoarthritis), and ligaments shorten and lose some of their elasticity.- Suffer from a painful and stiff knee which restricts daily activities likewalking.

The mechanism of locomotion in animals

Locomotion in an animal with a hydrostatic skeleton (earthworm)1. Earthworms have a hydrostatic skeleton (the force of contraction is applied to acoelum(fluid filled chamber).

2. Coelom is surrounded by two antagonistic muscle:a) circular muscles surround the chamberb) longitudinal muscles extend from one end to the other.

3. Thinner and longer:-When circular muscle contract and the longitudinal muscle relax.

4. Shorter and thicker:- When circular muscle relax and the longitudinal muscle contract.

5. The muscles contract rhythmically to produce peristaltic waves which begins atthefront and move towards the end of the body.

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6. Earthworm has chaetae (bristles) which anchor parts of the body to the ground sothatother parts can be pulled towards it.

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Locomotion in an animal with exoskeleton (grasshopper)

1. A grasshopper uses three legs to support the body off the ground, while the otherthreelegs move together to make successive steps while walking.2. The flexor and extensor (antagonistic) muscles are attached to the internal surface

of the exoskeleton.3. Flexor muscles bend a joint.4. Extensor muscles straighten it.5. The rear legs of a grasshopper are long and muscular and is adapted for hopping.

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6. Sitting position: When the flexor muscle contracts, the lower leg is pulled towardsthe body. The hind leg is folded in a Z shape and ready for a jump.7. Jump: When the extensor muscle contracts, the leg jerks backwards, propellingthegrasshopper forward and upward into the air.

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Locomotion in an animal with an endoskeleton (fish)

1. Why can a fish swim in a viscous and dense environment:a) body wight is supported by water to overcome gravity.

b) sleek and streamlined body to overcome resistance.c) overlapping scales on the body of a fish face backwards to overcome resistance.d) covered by slimy coating to minimize frictional drag and maintains a smooth flowof water.

2. Vertebral column of the fish is moved from side to side by the contractionandrelaxation of myotomes.

3. Myotomes W shaped muscle blocks that make up each side of the body of afish andcarry out opposite action.

4. Alternating waves of contraction and relaxation pass down the myotomeson either side of the body from the head to the tail.

5. These cause different parts of the body to be swept from side to sidepushing water backwards and sideways and the body forwards.

6. Tendency for a fish to become unstable in water during movement, leadingto:

-a) yawing sideways movementb) pitching vertical plane movementc) rolling transverse plane movement

7. Movements are countered by fins. Caudal fin provides thrust and controlsthe fishsdirection.

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8. These movements are countered by:-a) yawing resisted by the median (dorsal and ventral) finb) rolling resisted by median fin

c) Pitching resisted by paired pelvic fin and pectoral fin which acts as brakesandrudders.

. 9Bony fish have swim bladders to help them maintain buoyancy in thewater.

10. The swim bladder is a sac inside the abdomen that contains gas.

11. Controlling the amount of gas in the swim bladder, a fish can change itsbuoyancy sothat it has the same relative density as the surrounding water.

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2.2 Appreciating a Healthy Muscoskeletal System1. Adequte calcium intake2. Physical activities and exercise strengthen joint structures, increasemuscular performance and delay the progress of arthritis.

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2.3 Support in Plants

1. Why?a) Plant grows and it produces more leaves.b) Grow tall therefore needs to withstand the forces of gravity.

c) Spreading of leaves and branches horizontally.

2. Aquatic plants are supported by buoyancy and support.

Support in aquatic and terrestrial plants

Submerged plants1.Hydrilla

sp. have thin, narrow and flexible leaves.

2. This type of leaves provide little resistance to water flows, plants can be tugged atand pulled by water currents without being damaged.3. Air sacs inside the leaves and stems keep the plant floating close to the surfacetoobtain maximum sunlight.4. Their stems have no woody tissues.

Floating plants

1. Water hyacinth (Eichornia crassipes

) have broad leaves that are firm but flexibleenough to resist tearing by wave action.

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2.Aerenchyma tissues (spongy tissues with large air spaces between the cells) inthestems and leaves provide buoyancy so that the plants can float on the surface ofthewater.

Herbaceous plants (Terresterial plants)

1. Support provided by the turgidity of the parenchyma and collenchyma cells.2. Turgor pressure of the fluid content in the central vacuole pushes the cellmembraneand the cell contents against the cell wall, creating support for the stem, rootand leaves.3. The thickening of thecell walls with cellulose and pectin in collenchyma cellsprovideadditional mechanical strength.

Woody plants1. Supportprovided by sclerenchyma and xylem tissues.2. Sclerenchyma tissue is composed of cells with secondary cell walls that are

usuallylignified which support non-growing parts of plants.3. Two types of sclerenchyma tissue:a) fibres long, straight and thin

- found around vascular tissuesb) sclereids short, circular and irregular shaped- found in fruit andseeds

4. Duringprimary growth development, the cell walls of xylem vessels and tracheidsarethickened with lignin and forms vessels .

5. Type of vessels:-a) annular (ring shaped)vessel- b) spiral vesselc) scalariform (ladder like) vesseld) pitted vessel

6. Secondary growth of xylem results in the formation of wood which makes theplantstronger and and provides support..

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7. Other supporting structures:a) Buttress root roots that come out from the lower part of the trunk and grow intotheground, providing support for the tree.b) Creepers, vines and lianas use other trees for support.

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CHAPTER 3:

COORDINATIONAND RESPONSE

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Figures 1 andFigures show the components and organisation of the nervous system

Chapter 3 ( Coordination and Response )

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1. Organism respond to both external and internal stimuli to adapt to charges in theexternalenvironment and for survival.

2. The process that involves the reception of stimuli by the receptors, the intergration of

that information and the subsequent responses of the organism is called coordination.

3. The coordination process starts with the receptors receiving the stimulus and ends withtheeffectors producing a respone towards the stimulus.

4. Coordination in humans involves the nervous system and the endocrine system.

5. The nervous system consists of the central nervous system and the peripheral nervoussystem:a) The central nervious system is made up of the brain and the spinal cord.b) Theperipheral nervous system is mode up of the cranial nerves and the spinal verves.

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.

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The basic unit of the vervous system is the nerve cells called neurones.

1.There are three types of neurones:

a) afferent neurone which carries nerve impulses from the receptor to central nervous system.b) efferent neurone which carries nerve impulses from the central nervous system to theefferent neurone.c) interneurone which links the afferent neurone to the efferent neurone.

1. Synapse is a narrow gap between two neurones in contact.

2. Reflex action is an automatic response which does not involve the brain.

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1. The pathway of nerve impulses from receptor to effector to produce a reflex action is calledthereflex arc.

2. In a raflex action, the receptor detects the stimulus that are transmitted by the afferentneuroneto the spinal cord across a synapse, which are then transmitted by the efferent

neurone to theeffector to produce an autonomic response.

3. Nerve impulses are transmitted by the neurone in the form of electric signals but arethentranmitted across a synapse in the form of chemical signals by neurotransmitters.

4. E xamples of reflex actions are knee jerk and withdrawal from a hot object.

5. Coordination ny hormones involves the endocrine system.

6. The endocrine system coordinates the physiological processes of the bodythrough hormones.

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1. The endocrine system consists of endocrine glands:

Endocrine glands secrete hormones directly into the bloodstream.The hormones are then

carried bt the blood to the target organs, tissue and cells to produce a response.

Homeostasis is the process of regulating the physical and chemical factors in theinternalenvironment. It is inderpendent of unfavourable and fluctuating external conditions.

2. E xamples of processes regulated by homeostasis are :

a) regulation of blood osmatic pressure(by kidneys)b) regulation of blood sugar level (by liver and pancreas)

c) regulation of body temperature (by skin).

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1. Homeostasis occurs by negative feedback system. A deviation from the normal levelis detected and then the negative feedback mechanism is triggered to restore it to thenormal level.

2. The kidneys are involved in regulating the water nalance in the blood or the bloodosmotic

pressure.

3. Hence, the kidneys funcion as the osmoregulation and excretory organs.

4. Coordination by the nervous system is affected it to the drugs and alcohol.Drugs and alcoholaffect the functions of the transmitter and alter the transmission of nerveimpulses.

5. Tropism is a growth response of the shoot tips and root tips towards an externalstimulus.Thedirection of the response depends on the direction of the stimulus.

6. Tropism is controlled by the plant hormone called auxins. Auxins are produced in shoot tipwhich will diffuse away from the unilateral light into theshaded region of the elongation zone.Ahigher concentration of auxins in the shaded region of theshoot tip promotes cells elongation.

7. Hence, the shaded region grows faster and causes the shoot tobend and grow towards thelight,showing positive phototropism.

8. Roots grow downwards towards the pull of gravity,showing positive geotropism.

9. Auxins are used in agriculture to produce fruits from ovaries without fertilisation throughthe process called parthenocarpy.

10.Ethylene is a plant hormone in the form of gas that is used in agriculture to stimulatetheripening of fruits.