menstural cycle

Question 1

describe the follicular phase of the menstural cycle:

Answer 1

Folicular phase:
1. FSH stimulates secondary follicles to grow, as they do this the granulosa cells surrounding them release oestrodiol

2. increasing levels of oestrogen cause cervival mucus to become more permeable and allow penetration by a sperm to the cervix around the time of ovulation
3. one follicle will develop further and become the dominant follicle, LH will spike just before ovulation and cause the release of the release of the dominant follicle
4. the oestrogen that was being produced by the granulosa cells will have a negative feedback effect on the pituitary and reduce the amount of LH and FSH

Question 2

describe the luteal phase of the menstural cycle

Answer 2

Luteal phase:
5. after ovulation the follicle that was released becomes a corpus luteum and releases progesterone which maintains the endometrial linning and makes the cervical mucus thick so it cannot be penetrated

6. if fertilisation has occurred the syncithioblast of the embryo will release BHCG to maintain the corpus luteum
7. if no fertilisation and HCG the corpus luteum will degenerate and stop producing progesterone and small amounts of oestrogen and endometrial lining will break down
8. the lack of feedback from oestrogen and progesterone will cause the pituitary to start producing FSH and LH again

Question 3

when does ovulation occur?

Answer 3

14 days before the end of the menstural cycle

Question 4

which cells of the endometrium release prostaglandins?

Answer 4

stromal cells, prostaglandins encorouge endometrium to break down and the uterus to contract