K.C.S.E Biology Q & A - MODEL 2018PP2QN07
Describe the role of hormones in the human menstrual cycle.
answers
​After/at the onset of menstruation, (the anterior lobe of) the pituitary gland; secretes follicle stimulating hormone (FSH); the FSH causes the Graafian follicle; to develop into the ovary; and stimulate the ovary tissues to secrete oestrogen hormone; Oestrogen brings about repair/healing of the endometrium/uterine wall; its concentration increases to a level which stimulates the (anterior) pituitary gland; to secrete lutenizing hormone (L.H.) and stops further secretion of FSH;
The L.H. stimulates the maturation of the Graafian follicle; LH also stimulates the Graafian follicle to release an ovum into the (funnel of the) fallopian tube/causes ovulation; it also stimulates the remains of the Graafian follicle to form a yellow body/corpus luteum (in the ovary; The corpus luteum is stimulated by the L.H. to produce progesterone; Progesterone then stimulates the thickening of the endometrium/inner lining of the uterine wall; in readiness for implantation; as progesterone level increases, it inhibits (the pituitary gland) from secreting FSH; further increase in progesterone level inhibits the pituitary gland from secreting L.H. This causes the corpus Luteum to degenerate; this reduces the amount of progesterone; the sudden drop in secretion of progesterone causes the endometrium to slough off/menstruation occurs; and the cycle is repeated;
K.C.S.E Biology Q & A - MODEL 2014PP1QN06
State three roles of auxins in a plant stem.
ANSWERS
K.C.S.E Biology Q & A - MODEL 2012PP1QN25
State the role of the following hormones in the life cycle of insects:
ecdysone hormone; . juvenile hormone.
answers
K.C.S.E Biology Q & A - MODEL 1997PP1QN08
A person was found to pass out large volumes of dilute urine frequently.
Name the (a) Disease the person was suffering from (b) Hormone that was deficient
ANSWERS
​(a) Disease the person was suffering from
Diabetes inspidus ref. Diuresis/ water diabetes (b) Hormone that was deficient Antidiuretic hormone/ ADH/Vasopressin (a) Describe how insect pollinated flowers are adapted to pollination |
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