Describe the phases of the menstrual cycle and the role of hormones in each.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Define in one line. The menstrual cycle is the reproductive cycle of female primates, repeated about every 28 to 29 days from menarche to menopause.
2 · Menstrual phase. Lasts 3 to 5 days; the endometrium and its blood vessels break down because the ovum was not fertilised.
3 · Follicular phase. FSH and LH rise; primary follicles grow into a Graafian follicle that secretes estrogens; the endometrium regenerates.
4 · Ovulatory phase. LH and FSH peak at about day 14; the LH surge ruptures the Graafian follicle and releases the ovum.
5 · Luteal phase. The corpus luteum secretes progesterone, which maintains the endometrium for implantation.
6 · Draw the cycle. [Graph: LH, FSH, estrogen, progesterone and endometrium thickness against days 1 to 28, with the four phases marked]
7 · Link to daily life. Clean pads changed every 4 to 5 hours and safe disposal keep menstruation healthy.
8 · Close in one line. If fertilisation does not occur, the corpus luteum degenerates and a new cycle begins with menstruation.
Scoring tip: Name the hormone and where it comes from in every phase. Marks are lost when students write only 'hormones change'.
