Hormonal Control In The Menstrual Cycle

Question 1

Briefly describe the menstrual cycle in relation to hormones.

Answer 1

Gonadotropin releasing hormone - FSH - follicle develops - releases oestrogen - inhibits FSH - stimulates LH - ovulation occurs - Graafian follicle breaks down - corpus luteum releases progesterone - maintains endometrium - if implantation doesn’t occur FSH and LH reduce - progesterone reduces - endometrium breaks down

Question 2

Describe the structure of the Graafian follicle when it matures.

Answer 2

Forms a fibrous later called the Theca which secrets fluid into the cavity called the Antrum. FSH stimulates thecal cells to produce oestrogen. Secondary oocyte is surrounded by the zona pellucida and the corona radiata.

Question 3

What are the negative feedback mechanisms of the menstrual cycle?

Answer 3

Increases progesterone means LH decreases

Increases oestrogen means FSH decreases

Question 4

What are the positive feedback mechanisms of the menstrual cycle?

Answer 4

As GNRH increases, FSH increases

As oestrogen increases FSH and LH increase.