Describe What Is Happening In The Ovaries During The Reproductive Cycle

Question 1

Describe oogenesis ( maturation of ova )

Answer 1

During each cycle, one (or so) follicles mature.
Maturation is controlled by the hypothalamus secreting LHRH and anterior pituitary gland releasing gonadotrophin (group of hormones secreted by the pituitary gland) = FSH and LH. Both act on the ovaries.

Question 2

Describe the hormone role is in the first half of the cycle?

Answer 2

While the ovum is developing in the follicle, the follicle secrets increasing amounts of oestrogen.

Question 3

Describe the hormone role after ovulation?

Answer 3

The corpus luteum secrets primarily progesterone, with some oestrogen and inhibin

Question 4

Describe the development of one ovarian follicle before ovulation

Answer 4

The follicle starts as an immature (primordial follicle and then matures to a mature (graafian) follicle.
The follicle is filled with follicular fluid which increases.
The mature (graafian) follicle migrates from the cortex to the surface of the ovary.

Question 5

Describe the development of one ovarian follicle during ovulation

Answer 5

On day 14 of cycle, follicle ruptures, releasing the ovum into the peritoneal cavity.
The fimbriae catches it at the end of the uterine tube.
Cilia propel it along the uterine tube towards uterus.

Question 6

Describe the development of one ovarian follicle after ovulation

Answer 6

Corpus luteum develops and secrets progesterone (and oestrogen and inhibin)
Progesterone causes LH and FSH to decrease.
If ovum is NOT fertilised then falling LH level lead to degeneration and death of corpus luteum.
If ovum is fertilised then corpus luteum continues to secrete hormones for 3-4 months