Explain how blood pressure of human is regulated using negative feedback

mechanism (8marks)

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Describe the first and second line defense with appropriate examples

(8 marks)

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PUSAT TUISYEN CERGAS JAYA TOPICAL NOTES 1: TRANSPORT (Essay Practice )

PREPARED BY MR SUN (YOUR BIOLOGY COACH)

Listen . Recall . Practice

PUSAT TUISYEN CERGAS JAYA TOPICAL NOTES 1: TRANSPORT (Essay Practice )

PREPARED BY MR SUN (YOUR BIOLOGY COACH)

Listen . Recall . Practice

Explain how antibodies helps to fight and destroy microorganism in third line

defence mechanism. (8marks)

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Describe passive and active immunity (6marks)

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PUSAT TUISYEN CERGAS JAYA TOPICAL NOTES 1: TRANSPORT (Essay Practice )

PREPARED BY MR SUN (YOUR BIOLOGY COACH)

Listen . Recall . Practice

Explain how antibodies helps to fight and destroy microorganism in third line

defence mechanism. (8marks)

Antibodies are protein molecule that are produced by leucocytes. These antibodies are

having specific binding site to the antigens on the pathogens. Antibodies will bind to a

specific antigen and it will destroy the pathogens using four different methods. Lysin

antibody binds to the antigen of pathogen and causes the pathogen to disintegrate or break and

destroy by lysis process. Opsonin antibody will bind to the antigen of pathogen and act as a

marker for phagocyte to engulf via phagocytosis process and destroy the pathogen by fusing with

lysosome. This process known as Opsonisation. Agglutinin antibody will bind to the antigens of

many pathogens and causes the pathogens to clump together. Antibodies also will act as a marker

and allow the phagocytes to engulf the clump pathogen by phagocytosis process and fuse it with

lysosome. This prosess is known as agglutinisation. Antibodies also binds to toxin molecules

produced by pathogens. The antibodies binds to the toxin and avoid the toxin to have contact with

the body cells. This process neutralizes the toxin molecule. This process is known as

neutralization.

Describe passive and active immunity (6marks)

Immunity is divided in to two main categories that are active and passive immunity. Active

immunity is acquired either naturally or artificially and the immunity will last long for a life time.

Passive immunity is acquired either naturally or artificially. This immunity will show immediate

effect however it will not last long for a life time, it is just for temporary period of time.

Naturally acquired active immunity is obtained by infections (e.g Chicken pox virus or measle

virus). Earlier our body did not posses the specific antibody to fight against the infection. After

the virus introduce it self to our body then the leucocytes will respond by making new set of

antibodies that can bind to the antigen of the pathogen and destroy. Artificially acquired active

immunity is obtained through vaccination process. Vaccine is an inactivated viruses that resembles

the antigen of the real virus. This will make the body to produce new sets of antibodies that can

kill the virus if invaded. A person needs 2nd injection of vaccine to increase or boost the

individuals immunity to be above the immunity level so the immunity can last for a life time.

Naturally acquired passive immunity is obtained from mother to foetus through placent and

umbilical cord. The antibodies are transferred to the foetus through umbilical cord. After birth

the child is given mothers breast milk. Mothers milk contains good level of antibodies to help

increase the immunity of the child immediately and for a temporary period of time. Artificially

acquired passive immunity is obtained by individuals through injection of antiserum derived from

animals. These antiserum contains immunity that provides immediate immunity. The immunity level

drops gradually and vanishes after sometime. Artificially acquired passive immunity is obtained

when a person is infected with a specific pathogenic disease.

PUSAT TUISYEN CERGAS JAYA TOPICAL NOTES 1: TRANSPORT (Essay Practice )

PREPARED BY MR SUN (YOUR BIOLOGY COACH)

Listen . Recall . Practice

Explain how blood pressure of human is regulated using negative feedback

mechanism (8marks)

Normal blood pressure of a human is 120/80 mm Hg. 120 mmHg is the systolic pressure

(Condition when the ventricles contract) and 80 mm Hg is known as diastolic pressure (condition

when the ventricles relaxes). During strenuous exercise or vigorous activities or in fear the

individuals blood pressure increases. The high blood pressure is detected by the baroreceptors

located on the aorta arch and carotid vessels. These receptors will detect the stimuli and send

impulses to the cardiovascular centre located in the medulla oblongata. The cardiovascular

centre will send response through parasympathetic nerve to the heart and causes the heart to

have weaker contraction and lower heart beat rate. Responses are also sent to the blood vessels

and causes the blood vessels smooth muscle to relax and the vessels will cause vasodilation.

This action will make the lumen size of vessels to be bigger and reduces the resistance of blood

flow and finally reduces the blood pressure back to normal level. If the blood pressure of an I

ndividual drops below normal level, it is detected by the baroreceptors located on the aorta

arch and carotid vessels. These receptors will send impulses to the cardio vascular center

located in the medulla oblongata. The cardio vascular centre will show response through

sympathetic nerve and causes the heart to have stronger contraction and the heart beat rate

will increase. The blood vessels smooth muscle will contract and causes the blood vessels to go

through vasoconstriction. The lumen size will become smaller and creates resistance in the

blood flow. This increases the blood pressure until it reach normal blood pressure.

Describe the first and second line defense with appropriate examples (8 marks)

First and second line defence mechanism is non specific defence mechanism that protects

ourself from invasion of pathogenic microorganism. The first line defence mechanism consist of

skin, skin produces oil known as sebum that contains lysozyme that is used in killing the

microorganism. The skin also releases sweat that contains salt that kills the microorganism. The

dead skin is removed along the microorganism to avoid the growth of microorganism on our skin.

Or respiratory system is lined with epithelial goblet cells that has cilia and hair particles. It

also produces mucous to trap the dust and microorganism. Our eyes releases tears to clear dust

and microorganism. The tear also contains lysozyme to kill microorganism. Our digestive system

has stomach that produces hydrochloric acid with low pH value to kill the microorganism. If

microorganism successfully breached the first line defence, the second line defence mechanism

will take effect. In our interstitial space among the body cells there are many phagocytic white

blood cells (neutrophils/ monocytes/ macrophages) that will conduct phagocytosis to destroy

the microorganism by using its lysosome. If too many microorganism invaded then more

phagocytes will be present at the infected location.