Follicular Physiology

Question 1

Explain the hypothalamo-pituitary-gonadal axis relative to the LH surge causing ovulation

Answer 1

Corpus luteum (CL) releases progesterone which negatively feeds back to the hypothalamus. CL regresses, no more negative feedback, hypothalamus tonic center releases GnRH. Anterior pituitary releases FSH and LH which then cause growth and development of follicles on ovaries. Follicles produce estrogen which positively feeds back to the hypothalamus to release stimulate the surge center and release large quantity of GnRH to cause the LH surge to initiate ovulation

Question 2

Explain 2-cell, 2-gonadotropin model in Theca cells

Answer 2

LH binds Theca cells and induces synthesis of enzyme that catalyzes the reaction to convert cholesterol to testosterone which is then released

Question 3

Explain the 2-cell, 2-gonadotropin model in granulosa cells

Answer 3

FSH binds granulosa cells which stimulates synthesis of enzymes that convert testosterone (from Theca cells) to estrogen which is released into systemic circulation

Question 4

What effects does systemic estrogen have on the reproductive tract?

Answer 4

Increased blood flow
Increased Edema of tissues
Increased Secretion of mucus
Increased leukocytes
Increased smooth m. Motility
Growth of uterine glands to increase mucus
Affects brain to cause estrus symptoms