The Uterine Cycle

Question 1

What is the uterine cycle?

Answer 1

• a series of changes in the endometrium that is regulated by hormones

Question 2

What are the two main phases of the uterine cycle?

Answer 2

• changes in the endometrium
• menstruation

Question 3

What is the first step of the uterine cycle?

Answer 3

• oestrogen is secreted from the maturing follicles
• and starts the repair of the endometrium

Question 4

When does the repair of the endometrium occur?

Answer 4

• days 6 to 14 of the menstrual cycle

Question 5

What happens after the repair of the endometrium?

Answer 5

• under the influence of oestrogen and progesterone from the corpus luteum
• the endometrium continues to thicken, becoming more glandular (secretes mucus and nutrients) and vascular (has blood vessels)

Question 6

Why does the endometrium thicken and become glandular and vascular?

Answer 6

• to make it suitable for the implantation of a blastocyst

Question 7

What is a blastocyst?

Answer 7

• a fertilised egg

Question 8

What happens at the beginning of menstruation?

Answer 8

• the high levels of oestrogen and progesterone exert a negative feedback on the pituitary gland
• inhibiting the release of the hormones FSH and LH

Question 9

What happens as a result of the inhibition of the release of FSH nd LH?

Answer 9

• the corpus luteum degenerates and progesterone secretion is reduced and then stops

Question 10

What happens after progesterone secretion stops?

Answer 10

• with no hormone to maintain the endometrium, the lining breaks down and is shed

Question 11

What is menstruation?

Answer 11

• the process in which the endometrium breaks down and is shed

Question 12

What passes out through the vagina during menstruation?

Answer 12

• the detached tissue
• blood