Reproductive Physiology

Question 1

Define the luteal-placental shift.

Answer 1

Transition from steroid production by corpus luteum to steroid production by placenta which occurs in the first trimester of pregnancy

Question 2

What is the primary estrogen expressed in the reproductive years, during pregnancy, and after menopause?

Answer 2

Reproductive years - estradiol
Pregnancy - estriol
Menopause - estrone

Question 3

What is the primary source of testosterone in women?

Answer 3

Peripheral conversion from androstenedione

Other sources: ovaries, adrenal glands

Question 4

Describe the triggers for oocytes to pause & resume meiosis.

Answer 4

Primary oocytes are arrested at prophase I
At the beginning of each cycle a cohort of follicles is recruited & the oocytes resume meiosis I
Only the oocyte(s) destined for ovulation complete meiosis I (in response to LH surge)
This oocyte arrests at metaphase II
Meiosis II is complete only after fertilization

Question 5

Describe the two cell theory of ovarian steroidogenesis.

Answer 5

Theca cells express the enzymes needed to produce androstenedione (granulosa cells cannot produce androgens)
LH stimulates theca cells to produce androstenedione & testosterone
FSH stimulates aromatase expression in granulosa cells, resulting in conversion of androgens to estrogens

Question 6

True or false: ovulation alternates between ovaries.

Answer 6

False. Ovulation occurs randomly each month

Question 7

Describe the histologic effects of estrogen & progesterone on the endometrium.

Answer 7

Estrogen - proliferative endometrium, glands become tortuous but stroma remains compact
Progesterone - secretory endometrium (glycogen secretion into glandular lumen), glands become increasingly tortuous & stroma becomes edematous, spiral arteries increase in number & coiling

Question 8

What is the most common cause of acquired pituitary dysfunction?

Answer 8

Pituitary adenoma (prolactinomas most common)