week 10 pre lecture quiz

Question 1

Why might a person not ovulate?

Answer 1

-insufficient secretion of GnRH
-insufficient secretion of FSH
-insufficient secretion of LH
-production of excess prolactin

Production of insufficient amounts of GnRH, FSH or LH will prevent ovulation from occurring. GnRH is required to stimulate FSH and LH; FSH is required to develop follicles large enough to produce enough estradiol and to ovulate; LH is required for ovulation to occur.

Excess prolactin prevents ovulation by negatively feeding back onto the hypothalamus and pituitary.

Question 2

Treatment for infertility that is a result of no ovulation might include:

Answer 2

-estrogen antagonist (blocker)
-administration of hMG followed by hCG

By blocking estrogen receptors in the brain, we can increase GnRH/FSH/LH levels and induce ovulation in someone who is anovulatory. Also, hMG combines FSH and LH helps to develop follicles in anovulatory people, and following this with a bolus of hCG will cause ovulation of these newly-developed follicles.

Question 3

A person who ovulates may still have fertility problems if they:

Answer 3

-have blockage or kink in their oviducts
-might produce antibodies against partner’s sperm
-insufficient thickening of endometrium due to lower estrogen

Even if ovulation occurs, fertility can be a problem. If there is a blockage in the oviduct that prevents the sperm from reaching the ovum, fertilization cannot occur. If a blastocyst cannot implant in the endometrium, or if the endometrium is unable to be maintained due to low progesterone, pregnancy will not be maintained. It is, in fact, possible that a person’s immune system generates antibodies against their partner’s sperm, preventing fertilization.

Question 4

What might cause a low sperm count?

Answer 4

-low GnRH levels
-low FSH levels
-low LH levels
-retrograde ejaculation

If any part of the GrRH/FSH/LH pathway is not functioning, sperm production will be dramatically reduced (if it proceeds at all). Also, retrograde ejaculation is a condition in which semen is ejaculated backward in the urethra to the bladder, instead of out the penis, resulting in low sperm count.