Reproductive System Physiology 1 - Teel

Question 1

Sexual differentiation of Gonads in Male / Female

Answer 1

Primordial gland: cortex and medulla

Male embryo: primordial germ cells migrate from cortex to medulla -> sex cords become seminiferous tubules

Female: Medulla regresses while cortex thickens, primordial germ cells form oocytes

Question 2

Differentiation of internal ducts in Male / Female

Answer 2

Male: Wolffian ducts develop into vas deferens, seminal vesicles and ejaculatory ducts. Regression of Mullerian ducts dependent on AMH (anti-mullerian hormone)

Female: Mullerian ducts develop into fallopian tubes, uterus, upper third of vagina. testosterone / AMH = absent.

Question 3

Delete this card:

sKIPPIng beginning, starting at 14:20

Question 4

Male Reproductive System:

From Ant. Pit. to LH and FSH to end pdt.

Answer 4

Hypothalamic GnRH reach ant. pit. Gonadotropin cells, stimulates secretion of FSH and LH

LH targets Testis, stimulating leydig cells, which produce testosterone -> androgenic effects. Testosterone also does negative feedback, stopping LH release.

FSH same pathway, but stimulates sertoli cells in testis. Stimulates spermatogenesis, and inhibin. Inhibin does negative feedback, stopping FSH release.

Question 5

Steroidogenesis:

Answer 5

Start with cholesterol -> Pregnenolone (via CYP 450 cells) -> DHEA -> Androstenediol -> Testosterone

Question 6

What does testosterone do when it comes to a target cell that happens to have a receptor?

Answer 6

Normally nuclear receptors. Free testosterone enters target cells, binds to high affinity nuclear androgen receptor, or converted to DHT.

Most converted to 17-ketosteroids in liver or DHT in prostate.
Metabolites conjugated / excreted in urine.

Question 7

Spermatogenesis:

Answer 7

Primordial cells (spermatogonium) in wall of seminiferous tubules migrate to lumen via tight junctions of sertoli cells. Mitosis / Meiosis occur as they migrate to lumen.

Question 8

Relationship between Leydig and Sertoli Cells

Answer 8

Both synthesize new proteins. Leydig cells convert cholesterol to testosterone which travels through bloodstream / barriers and enter sertoli cells.

Question 9

Sperm maturation in the epididymis

Answer 9

Initially: spermatids are not very mobile
Progressive increase in motility
Maturation of acrosome
Ability to bind zona pellucida

Question 10

Semen:

components

epididymis empties into…

Answer 10

10% sperm cells, 70% secretions from seminal vesicles, pH is alkaline, contains fructose, vitamins, electrolytes

Epididymis empties into vas deferens which connects with the duct from seminal vesicles -> ejaculatory duct.

Question 11

Male Sex Act

Erection

Answer 11

Parasympathetic neurons release ACh, NO, and VIP. Corpus cavernosum / corpus spongiosum become engorged with blood.

NO acts as a vasodilator through second messenger cGMP.

Question 12

Male Sex Act

Ejaculation

Answer 12

Sympathetic control. Rhythmic contractions of smooth muscle in distal epididymis, vas deferens, and accessory glands eject semen.

Question 13

Infertility in Male

Answer 13

Too few sperm
Too many abnormal sperm

Question 14

Female Reproductive System

Starts in hypothalamus

Answer 14

GnRH secreted in pulses from hypothalamus
Stimulates secretion of FSH and LH by gonadotrophins in ant. pit.
Targets Theca and Granulosa cells in Ovary (Male was leydig / sertoli in testis)
Theca cells release progestins / androgens
Granulosa cells release estrogens, activin, inhibin, progestins