57 Reproduction

Question 1

What are the different stages of the menstrual cycle and stages of the uterus lining? How do these compare?

Answer 1

• Prior to ovulation, there is the follicular phase -> This corresponds to the proliferative phase of the uterus
• After ovulation, there is the luteal phase -> This corresponds to the secretory phase of the uterus
• Finally, there is menstruation

Question 2

What are the 3 phases of the uterine cycle?

Answer 2

• Proliferative
• Secretory
• Menstrual

Question 3

What hormones control the proliferative and secretory phases of the uterine cycle?

Answer 3

• Proliferative -> Estrogen
• Secretory -> Progesterone

Question 4

What happens during the proliferative phase?

Answer 4

Proliferative phase:

• Endometrium is exposed to oestrogen as a result of FSH and LH stimulating its production
• Oestrogen stimulates repair and growth of the functional endometrial layer allowing recovery from the recent menstruation.

Question 5

What happens during the secretory phase?

Answer 5

Secretory phase:

• Occurs after ovulation
• Driven by progesterone from the corpus luteum.
• Endometrial glands secrete various substances that will facilitate implantation

Question 6

What happens during the menstrual phase?

Answer 6

Menstrual phase:

• At the end of the luteal phase, the corpus luteum degenerates (if no implantation occurs), which results in decreased progesterone production.
• This causes the spiral arteries in the functional endometrium to contract.
• Endometrium is shed and exits through the vagina as menstruation.

Question 7

Which days of the menstrual cycle does each part of the uterine cycle occur in?

Answer 7

• Menstruation -> Days 0 to 7
• Proliferative -> Days 7 to 14
• Secretory -> Days 14 to 28

Question 8

What are the effects of estradiol, progesterone and prostaglandins on the uterine cycle?

Answer 8

• Estradiol -> Promotes proliferation and apiral artery development
• Progesterone -> Glandular secretion
• Prostaglandins -> Arterial spasm and uterine muscle spasm

Question 9

What are the two zones of the uterus lining?

Answer 9

• Basal zone -> Not sloughed during menstruation
• Functional zone -> Sloughed during menstruation and then regenerates

Question 10

Describe what causes menstruation to occur.

Answer 10

• At the end of the luteal phase, the corpus luteum degenerates (if no implantation occurs).
• The loss of the corpus luteum results in decreased progesterone production.
• The decreasing levels of progesterone cause the spiral arteries in the functional endometrium to contract.
• The loss of blood supply causes the functional endometrium to become ischaemic and necrotic.