Male Reproductive Physiology Flashcards
(29 cards)
Where do primordial germ cells migrate and what do they ultimately become?
-migrate into future testes and become spermatogonia
What do spermatogonia do?
-begin mitotic division at puberty and become primary spermatocytes
What do primary spermatocytes do?
-complete the first half of meiosis and become secondary spermatocytes
What do secondary spermatocytes do?
-complete the second half of meiosis and become spermatids
What do spermatids do?
-undergo differentiation to become mature sperm
Where are Sertoli cells located?
-within the seminiferous tubules
What is the function of Sertoli cells?
- act as nurse cells (sustentacular cells) that surround primary spermatocytes and nurse them through the process of spermatogenesis and spermiogenesis
- form estrogens and testosterone important for spermiogenesis
What happens during spermiogenesis?
- proacrosomal vesicles coalesce to form acrosome (hyaluronidase and proteolytic enzymes)
- nucleus becomes highly condensed
- acrosome caps nucleus
- centrioles migrate to side of nucleus opposite acrosome
- distal centriole begins to organize flagellum
- mitochondria move to base of forming flagellum and wrap around it
- excess cytoplasm a is sloughed off as residual body
Where are sperm cells stored until ejaculation?
-epididymis, requires several days to pass through
How long must sperm remain in the epididymis?
-minimum of 18-24 hours in order to gain motility
Where are Leydig cells found?
-interstial spaces in testes
What is the function of Leydig cells?
-secrete testosterone
What stimulates the Leydig cells?
- LH secreted by anterior pituitary
- FSH is also necessary for spermatogenesis
What are the two male accessory glands?
- seminal vesicles
- prostate gland
Where are the seminal vesicles?
- paired structures behind the prostate
- each vesicle is a loculated tube lined with secretory epithelium
What is in the mucosa material that the seminal vesicles secrete?
- fructose
- citric acid
- additional nutrients
- prostaglandins
- fibrinogen
What happens to the seminal vesicles during emission and ejaculation?
- contents of vesicles are emptied into ejaculatory ducts contains sperm
- 60% total volume of semen
- fructose provides energy for sperm
- prostaglandins make cervical mucus more receptive to sperm movement and may causes retro-peristaltic contractions of uterus and Fallopian tubes
What happens to the prostate gland during emission and ejaculation?
- 30% total volume of semen
- milky fluid containing Ca, citrate ions, phosphate ions, clotting enzyme, and profibrinolysin
- slightly alkaline fluid -> helps neutralize acidity of other seminal fluids and vaginal secretions of the female
What is an androgens? What does this include?
- any steroid hormone that has masculinizing effects
- testosterone
- dihydrotestosterone
- androstenedione
What can androgens be synthesized from?
-can be synthesized in testes and adrenal glands from cholesterol and acetyl CoA
What forms testosterone?
- Leydig cells
- cells are numerous in newborn males and adult males after puberty
- almost nonexistent in testes during childhood
What happens to testosterone after secretion?
- 97% is loosely bound with albumin or tightly bound with beta globulin
- circulates in blood for 30mins to several hours
- transferred to tissues or degraded to inactive products that are subsequently secreted
What happens to testosterone that enters tissue?
-mostly converted to dihydrotestosterone especially in prostate and in fetal external genitalia
What happens to testosterone that is not fixed in tissues?
- converted in lover to androsterone and dehydroepiandrosterone
- conjugated as either glucuronides or sulfate so
- excreted into gut via bile or urine via kidneys
