The menstrual cycle and how it is influenced by different hormones.

Describe the menstrual cycle and how it is influenced by different hormones.


The menstrual cycle is a series of events that occur in the female body to:


 prepare it for possible pregnancy/
 Which involves ovarian cycle/
 and the uterine cycle/
 It takes an average of 28 days /
 The pituitary gland //hypophysis
 secretes FSH/
 which stimulates the development of a primary follicle/ in the ovary


The developing follicle/Graafian follicle:


 secretes oestrogen/
 which stimulates the thickening of the lining of the uterus/endometrium
 Around day 13, the pituitary gland/hypophysis
 secretes LH/
 which cause ovulation to occur/


The remains of the Graafian follicle develops into the corpus luteum which secretes
progesterone:


 which continues to stimulate the thickening of the uterus/
 High levels of progesterone/
 inhibits the production of FSH/
 so that the ovaries are no longer stimulated to produce another follicle/
 If fertilisation does not occur, the corpus luteum degenerates/
 and stops producing progesterone/
 The pituitary gland/hypophysis is no longer inhibited in its production of
 FSH/ and a new follicle develops
 The thick endometrium is no longer maintained/ it degenerates
 and is shed together with blood/menstruation takes place
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