(a)(i) What is an endocrine gland? [2 marks]
State three functions of adrenalin. [3 marks]
(b) State three effects of each of the following conditions in humans:
(i) over-secretion of thyroxin;
(ii) under-secretion of thyroxin.[6 marks]
(c) (i) Write HIV in full. [ 1 mark]
(ii) Distinguish between HIV and AIDS. [2 mark]
(d)State two methods each by which the vectors of the following diseases can be controlled:
(iii) guinea worm. [ 6 marks]
This question was attempted by few candidates and candidates performance was fair. In part (a)(i)
candidates could not define endocrine gland correctly in (a) (ii) candidates lost marks because they
cannot state functions of adrenalin. In part (b) however, candidates lost marks because they mixed
up effect of over-secretion of thyroxin with effect of under-secretion of thyroxin. In part ( c) (i)
candidates lost marks due to their inability to write HIV in full, some candidates wrote Human
immino deficiency while some wrote immune only, in (c) (ii) candidates could not distinguish
between HIV and AIDS. In part (d) candidates could not state the method of controlling the vectors
of onchocerciasis, schistosomiasis and guinea worm, few candidates that stated the methods mixed
up onchocerciasis for guinea worm and schistosomiasis for onchocerciasis.
The expected answers were as follows
(a)(i) Endocrine gland
Is a gland whose secretion does not pass through any duct/ductless before reaching its target
organ/ductless gland which secretes directly into the blood.
(ii) Functions of adrenal in
increasing the rate of conversion of glucose to glycogen
controls response for fight or flight/prepares the body for action
increases the rate of heart beat
it increases muscle tones
it increases rate of breathing action
increases blood sugar level. (b) Effects of the following conditions in humans
(i) Over-secretion of thyroxin
thyroid gland becomes large/goiter develops
increases rate of heart beat
large appetite is developed
there is loss in body weight
rate of metabolism is increased
increase in blood pressure
(ii) Under-secretion of thyroxin
rate of metabolism decreases
rate of heart beat decreases
body temperature is lowered
children become stunted in growth
children have poor mental development
adults develop thick skin.
(c) (i) HIV in full
Human Immuno Deficiency Virus
(ii) Distinguishing between HIV and AIDS
HIV is a virus and AIDS is a disease caused by the virus
(d)Method by which the vectors of the following diseases can be controlled
clear bush around banks of river/allow free flow of stream.
treat breeding places with insecticides
Introduce fish to eat intermediate host (water snail)
eliminate the water snail with mollusc ide
clear vegetation around pond/destroy breeding grounds
prevent infected person from urinating or defecating into waters
avoid bathing in infected water.
boil drinking water/provide good source of water.
filter water before drinking
avoid wading or bathing in water/streams.
rivers/lakes/ponds wear rain boot.
destroy intermediate host.