12.12.2 Hormonal Events during the Female Reproductive Cycle

Question 1

Hormonal Events during the Female Reproductive Cycle

Answer 1

• The female reproductive cycle consists of the ovarian cycle and the uterine cycle, which are both controlled by hormones.
• The ovarian cycle involves the growth of the follicle and the release of an egg. When the egg is released, the follicle becomes the corpus luteum. The corpus luteum releases hormones involved in the completion of the reproductive cycle.
• The uterine cycle includes the shedding and subsequent build up of the endometrium.

Question 2

uterine cycle

Answer 2

• Hormones control both the uterine cycle and the
  ovarian cycle. The hypothalamus in the brain releases
  gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release small amounts of
  follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
• The immature follicle has FSH receptors. FSH binds these receptors and triggers the follicle to grow and take up water

Question 3

corpus luteum

Answer 3

• The top half of the diagram to the left shows the relative levels of LH and FSH in the plasma. Note that levels of LH and FSH are relatively low during the first half of the cycle. During the follicular stage, low levels of estrogens, which are secreted by the growing follicle, inhibit LH and FSH production.
• At about mid-cycle, estrogensecretion from the follicle rises sharply. High levels of estrogen in the blood stimulate the increased release FSH and the LH surge. The follicle now has LH receptors and responds to the LH surge by maturing and releasing the egg (ovulation).
• After ovulation, the corpus luteum that develops from the ruptured follicle releases estrogen and progesterone. Together these hormones inhibit the secretion of LH and FSH and stimulate the development of the endometrium.
• As the corpus luteum disintegrates because of low LH levels, estrogen and progesterone levels decline and trigger menstruation.

Question 4

Match the following hormones with their role in the menstrual cycle.

1. estrogen
2. LH
3. FSH
   a. stimulates follicular growth
   b. stimulates proliferation of the endometrium
   c. stimulates secretion of progesterone
   d. stimulates secretion of estrogen

Answer 4

1. b
2. c, d
3. a, d

Question 5

Which of the following hormones do not have a concentration peak around day 14 of the menstrual cycle?

Answer 5

• progesterone

Question 6

Which of the following hormones produced by the anterior pituitary gland help regulate the menstrual cycle?

i. follicle-stimulating hormone (FSH)
ii. lutenizing hormone (LH)
iii. growth hormone (GH)
iv. prolactin

Answer 6

• i, ii

Question 7

Progesterone is secreted after ovulation by the

Answer 7

• corpus luteum.

Question 8

Which of the following is not a function of estrogen?

Answer 8

• Estrogen signals the corpus lueteum to produce progesterone.

Question 9

Estrogen is secreted throughout the menstrual cycle by the

Answer 9

• ovaries

Question 10

What hormone maitains the uterine lining after fertilization?

Answer 10

• HCG