Question
The menstrual cycle is coordinated by hormones secreted by the pituitary gland and hormones secreted by the ovaries.
Fig. 3.1 shows some of the events that occur during the menstrual cycle.
(a) Put the stages into the correct sequence. Two have been done for you.
(b) (i) Describe what happens at ovulation.
(ii) Name the cell produced at fertilisation by the fusion of two gametes.
(c) If an embryo implants in the uterus, the embryo secretes a hormone known as hCG that stimulates the reproductive organs of the woman to continue to secrete progesterone.
Describe what happens after fertilisation until the time that the embryo secretes hCG.
(d) State two places where progesterone is produced during pregnancy.
(e) (i) Fertility drugs are taken to increase the chance that a woman may become pregnant.
Describe and explain how these drugs improve the chances of becoming pregnant.
(ii) Outline two social implications of using fertility drugs.
Answer/Explanation
Ans:
(a) either KMJ ; ON ;
or KMO ; JN ;
(b) (i) release of an, egg/ ovum/ oocyte ;
either
from, follicle/ ovary ;
or
into, oviduct/ fallopian tube ;
(ii) zygote;
(c) zygote/ fertilised egg, divides ;
mitosis / cell division ;
forms, an embryo ; A blastocyst/ blastula
(hollow) ball/ collection/ group/AW, of cells ;
goes /moves, down oviduct/down fallopian tube/ towards uterus ;
detail, e.g. ciliary action/ peristalsis / muscle contraction ;
implants /AW, into, lining of the uterus / endometrium/wall of uterus ;
growth/ development, of placenta ;
follicle becomes, yellow body / corpus luteum/remains of follicle/AW ;
yellow body / corpus luteum/ ovary /AW, secretes /releases / produces
progesterone ;
progesterone maintains, endometrium/ lining of uterus /wall of
uterus /AW ;
progesterone, prevents menstruation ;
inhibition of FSH (secretion/release) ;
prevents, production of more eggs / production of follicles ;
(d) corpus luteum/ yellow body /ovary ;
placenta ;
(e) (i) (named) drug, injected/ taken, early in menstrual cycle ;
inhibits action of oestrogen ;
stimulates, production/release, of FSH ;
makes sure that FSH concentration is high enough ;
to stimulate production/ development/ maturation of, follicles / eggs /
ova/oocytes ;
more eggs are released ;
LH stimulates, ovulation/release of eggs ;
(ii) idea that stress is associated with difficulty having children ;
stated problem with multiple births ;
problems with unused embryos (when used with IVF) ;
issues with elderly parent(s) ;
religious objections to use of fertility drugs ;
any reference to cost of the treatment ;
increases populations / any negative effect of population increase ;
can be used to increase populations /any positive effect of population
increase ; e.g. in countries with falling birth rates