The Menstrual Cycle

Question 1

At what age does thelarche (braest development) usually start?

Answer 1

9-11 years.

Question 2

At what age does adrenarche (pubic hair development) occur?

Answer 2

11-12 years.

Question 3

At what age does menarche usually aoccur?

Answer 3

13 years.

Question 4

In the menstrual cycle, describe what happens during menstruation.

Answer 4

Day 1 - 4

The myometrium contracts and the endometrium is shed.

Question 5

In the menstrual cycle, describe what happens during the proliferative phase.

Answer 5

The Proliferative Phase (Day 5-13)

1. Pulses of GnRH from hypothalamus which cause an increase in LH and FSH
2. Increased LH and FSH induce follice growth which causes a release of oestradiol and inhibin.
3. Oestradiol and inhibin cause a negative feedback loop and suppress FSH.
4. Oestradiol causes a positive feedback loop and causes a surge in LH–> ovulation occurs.
5. Oestradiol causes proliferation of the endometrium.

Question 6

In the menstrual cycle, describe what happens during the secretory phase.

Answer 6

The Secretory Phase (Day 14-28)

• The follice becomes a corpus luteum and produces MORE Progesterone than oestradiol.
• Progresterone causes secretory changes (glands swell and increased blood supply to uterus.
• If no fetrilization then corpus luteum dies and you have decreased oesterogen and progresterone.