Male Reproductive System Flashcards
Spermatogenesis takes about……
74 days
Describe the role of the following hormones in spermatogenesis:
1. Testosterone
2. LH
3. FSH
4. Estrogen
5. GH
- Stimulates maintenance & development of germinal epithelium, needed for mitotic & meiotic divisions
- Acts on Leudig cells to produce testosterone
- Acts on Sertoli cells to activate their role in spermatogenesis by facilitating spermatid maturation to spermatozoa & promoting production of ABG
- Formed from testosterone by Sertoli cells, essential for spermiogenesis
- Promotes early division of spermatogonia. Its absence can lead to infertility
What is effect of high PRL level on males?
Inhibits testosterone synthesis via inhibition of GnRH, LH & may produce infertility in adult males
The suitable tempertaure for spermatogenesis is…….
32-35degC
Normally testes descend into scrotum at…….under effect of……
7th month of pregnancy
Fetal testosterone
Testes are kept cool by:
- Circulating air around scrotum
- Heat exchange in a countercurrent fashion between the spermatic arteries & veins
- Absence of subcutaneous fat in the scrotum
List functions of Sertoli cells
- Form blood testis barrier
- Provide nutrition for developing sperms by their glycogen content
- Have phagocytic function (engulf cytoplasm extruded from spermatids & destroy defective germ cells)
- Secretion of fluid into lumen of seminiferous tubules that pushed sperms into epididymid
- Secretion of ABG
- Site of action of testosterone & FSH
- Secretion of hormone inhibin that inhibits FSH
- Secrete Mullerian-inhibiting factor that cause regression of Mullerian duct
- Formation of estrogen by aromatase
What is the function of epididymis?
- Most sperms are stored in epididymis
- Epididymis concentrate sperm 100-fold by absorbing most fluid that enters seminiferous tubules
- Sperm leaveing the testes are not fully motile, they continue their maturation & acquire motility during passage in epididymis
How does sperms acquire motility?
The Catsper (alkaline-sensitive Ca++) channels are sperm-specific, Ca++ permeable, pH dependent, present in the membrane of sperm tail. They become more active as the sperm pass from acidic vaginal secretion to alkaline cervical mucus causing Ca++ entry into sperm cells which is crucial for fertility. Ca entry is necessary for capacitation, hyperactivated motility & the acrosome reaction.
Describe func of seminal vesicles
Secretes fluid that:
1. Dilutes the thick mass of sperm that make them immobile
2. Provides more than half of semen thus helps push seprm into urethra
3. Contains fructose & citric acid used as nutrient for the ejaculated sperm
4. Contain fibrinogen that helps clot semen in vagina immediately after ejaculation
5. Contains prostaglandins which help fertilization by reacting with female cervical mucus to help rapid passage of the sperm into uterus, induce reverse peristaltic contraction in the uterus & fallopian tubes to move sperm toward the ovaries.
Describe functions of prostate gland
Secretes a thin milky fluid:
1. Is slightly alkaline helps to neutralize the acidity of the fluid of vas deferens and of vaginal secretion & thus inc motility & fertility of sperm
2. Contains calcium, citrate & phosphate ions
3. Contains clotting enzymes (act on fibribogen from seminal vesicles to clot the semen in female reproductive tract during withdrawal of penis) & fibrinolysin (dissolve clot after few minutes to release sperms)
The normal volume of semen is……
Percentages is…..(sperm), ………(seminal vesicle fluid),……..(prostate)
2-4 ml per ejaculation
10%, 30%, 60%
Normal sperm count is……., while……is considered sterile.
60-100 million/ml
20 million/ml
Sperm normally live ……in female genital tract but can live for several yrs at temp…..
72 hrs
-100degC
Normally 60% of sperm are motile after …….
6 hrs