The Menstrual Cycle

Question 1

What is the term given to describe the inception of menstruation around puberty?

Answer 1

Menarche

Question 2

What triggers the menarche?

Answer 2

Increasing GnRH levels

Question 3

What comprises an ovarian follicle?

Answer 3

An oocyte surrounded by granulosa and theca cells

Question 4

What is the function of theca cells?

Answer 4

Produce androgens

Question 5

What is the function of granulosa cells?

Answer 5

Conversion of androgens (using aromatase) to oestrogens

Question 6

What are the two key phases of the menstrual cycle?

Answer 6

1. Follicular phase
2. Luteal phase

Question 7

Which days does the follicular phase typically occupy within the menstrual cycle?

Answer 7

Days 1 - 12

Question 8

The follicular phase begins with __________

Answer 8

The follicular phase begins with menstruation

Question 9

Which hormone begins to rise first in the follicular phase and what is its impact?

Answer 9

Gonadotrophin releasing hormone (GnRH)

Increases secretion of FSH and LH from the anterior pituitary

Question 10

Which hormone acts on theca cells and what is the outcome?

Answer 10

LH

Androgen production

Question 11

Which hormone cats on granulosa cells and what is the outcome?

Answer 11

FSH

Oestrogen production

Question 12

___________ levels rise throughout the follicular phase

Answer 12

Oestrogen levels rise throughout the follicular phase

Question 13

____ causes maturation of follicles until a _________ (dominant) follicle emerges

Answer 13

FSH causes maturation of follicles until a Graafian (dominant) follicle emerges

Question 14

Between which days does a surge in LH occur and what does it cause?

Answer 14

12-14

Ovulation

Question 15

High levels of oestrogen have what impact on which hormone?

Answer 15

Inhibition of FSH

Question 16

What happens to the remaining follicle after ovulation?

Answer 16

It becomes the corpus luteum and secretes progesterone (and some oestrogens)

Question 17

What effect does progesterone have?

Answer 17

1. Increases thickness and secretory activity of endometrium
2. Increases basal body temperature
3. Increases cervical mucus thickness
4. Aids glandular development in the breasts

Question 18

What effect do high progesterone levels have on which two other hormones?

Answer 18

Inhibition of FSH and LH

Question 19

What happens when there is failure of fertilisation?

Answer 19

1. Degeneration of the corpus luteum
2. Fall in progesterone levels
3. Fall in oestrogen levels
4. Vasospasm of of arterioles supplying endometrium
5. Necrosis of endometrium and menstruation

Question 20

A fall in progesterone levels has which effect on which two other hormones?

Answer 20

Rise in FSH and LH

(inhibitory effect removed)

Question 21

What is the most potent oestrogen produced and what does it cause?

Answer 21

Oestradiol

1. Secondary sexual charcateristics
2. Contributes to bone and CV health

Question 22

Which hormone stimulates the transformation of the empty follicle to the corpus luteum?

Answer 22

LH