Menstruation

Question 1

What is the sequence of puberty in females?

Answer 1

Breast buds
Growth of pubic hair
Axillary hair
Menses begin

Question 2

What is menarche?

Answer 2

A girl’s first period

Question 3

What is the mean age for puberty in girls?

Answer 3

13 years

Question 4

At what age should you start investigations if no periods?

Answer 4

15 years

or no signs of puberty by 14

Question 5

What axis controls the menstrual cycle?

Answer 5

hypothalamic-pituitary-ovarian axis

Question 6

Describe the hypothalamic-pituitary-ovarian axis.

Answer 6

1 - pulsatile production of gonadotrophin releasing hormone (hypothalamus)
2 - stimulates pituitary - produces gonadotrophin (LH, FSH)
3 - FSH stimulates follicle development and granulosa cells in ovary to produce oestrogen
4 - increased oestrogen inhibits production of FSH by negative feedback

Question 7

What is day 1 of the menstrual cycle?

Answer 7

The first day of menstruation

Question 8

Describe what happens from day 1 of the menstrual cycle.

Answer 8

• follicular phase:
• first 4 days - FSH levels high (stimulating primary follicle development)
• primary follicle produces oestrogen (stimulating development of glandular ‘proliferative’ endometrium and of cervical mucus receptive to sperm)
• increased oestrogen inhibits FSH production (neg feedback)

Question 9

When does ovulation occur?

Answer 9

14 days before onset of menstruation

Question 10

Describe the process of ovulation.

Answer 10

• 14 days before menstruation, oestrogen levels become high enough to stimulate LH surge
• stimulates ovulation (dominant follicle ruptures releasing oocyte)
• once ovum released, primary follicle becomes corpus luteum (luteal phase) and produces progesterone
• causes endometrial lining to prepare for implantation

Question 11

How does the endometrial lining prepare for implantation?

Answer 11

Glands become convoluted (secretory phase)

Question 12

What happens if the ovum isn’t fertilised?

Answer 12

• Corpus luteum breaks down, hormone levels decrease
• spiral arteries in endothelial lining constrict - lining sloughs
• menstruation

Question 13

When does menstruation occur?

Answer 13

14 days post ovulation

Question 14

What is the corpus luteum?

Answer 14

primary follicle after releasing ovum

Question 15

What is the average length of a menstrual cycle?

Answer 15

28 days (Can range from 21 to 35)

Question 16

What does the LH surge cause?

Answer 16

Ovulation

Question 17

What stimulates the LH surge?

Answer 17

High levels of oestrogen

Question 18

What hormone does the corpus luteum produce?

Answer 18

Progesterone