Negative Feedback Loops in the Menstrual Cycle

Question 1

What happens in step 1 of the negative feedback loop in the menstrual cycle?

Answer 1

• under the influence of FSH a primary follicle develops into a Graafian follicle
• and causes the ovaries to produce oestrogen

Question 2

What happens in step 2 of the negative feedback loop in the menstrual cycle?

Answer 2

• oestrogen then stimulates the pituitary gland to produce LH

Question 3

What happens in step 3 of the negative feedback loop in the menstrual cycle?

Answer 3

• LH causes the Graafian follicle to form the corpus luteum
• which secretes progesterone

Question 4

What happens in step 4 of the negative feedback loop in the menstrual cycle?

Answer 4

• the increased progesterone and oestrogen concentrations activate the negative feedback mechanism
• which stops the pituitary glands secreting FSH and LH

Question 5

What happens in step 5 of the negative feedback loop in the menstrual cycle?

Answer 5

• as there is no FSH a Graafian follicle will not develop
• and no oestrogen and progesterone will be released by the ovary

Question 6

What happens in step 6 of the negative feedback loop in the menstrual cycle?

Answer 6

• because of the low levels of oestrogen and progesterone
• the secretion of FSH an LH is no longer suppressed
• the whole cycle starts again