Flashcards in Male Repro Deck (14)
What are the 4 accessory glands of the male reproductive system?
Seminal vesicles, prostate gland, bulbourethral (Cowper's) glands, and the penis
The seminiferous tubules are lined with what two populations of cells?
Germinal epithelium (spermatogenesis takes places)
Sertoli cells (supportive or "nurse" cells) - narrow cells extending from the base of the seminiferous tubule to the lumen
What is spermatogenesis?
Process of spermatogonia (stem cells) --> spermatozoa
What is the blood-testis barrier and what does the blood-testis barrier divide?
Why is it important?
Sertoli cell cytoplasmic processes that form occluding junctions (separates basal compartment - containing spermatogonia - from adluminal compartment - containing cells undergoing meiosis)
Spermatogonia from primary spermatocytes
Meiosis in primary spermatocytes generates cells that can be recognized as foreign by the immune system (due to rearrangement of xsomes and the appearance of new cell surface markers) - B-T barrier needed to keep these "new" cells away from the immune system / Also imp to maintain high local concentration of testosterone from Leydig cells
What is spermatogenesis?
Where does it take place?
What are the four phases?
Subdivision of spermatogenesis: Conversion of spermatids --> spermatozoa
Process takes places while spermatids are embedded in Sertoli cells' cytoplasm
Divided into 4 phases:
1. Golgi phase (hydrolytic enzymes are sorted from the golgi apparatus to the acrosomal vesicle)
2. Cap phase (acrosomal cap forms)
3. Acrosomal phase
4. Maturation phase
What is Kartagener's syndrome?
Immotile cilia syndrome (cilia lack dynein, the ATPase-containing protein that forms the "arms" on the microtubules in cilia and flagella)
Males with this disorder are sterile and both sexes suffer from chronic sinusitis and bronchitis due to the inability to clear the respiratory passages
Endocrine functions of Sertoli cells:
What do they secrete? (6)
ACTIVIN (promotes FSH release) and INHIBIN
FSH acts on seminiferous tubules to increase spermatogenesis AND on interstitial cells to increase their sensitivity to LH
Sertoli cells also secrete ESTROGEN that is thought to have some sort of regulatory role.
ANDROGEN BINDING PROTEIN (ABP) - essential to keep level of testosterone high inside seminiferous tubules
TESTOSTERONE & ANTI-MULLERIAN FACTOR (ensure that Wolffian ducts will develop)
Testosterone production stops before birth and resumes at puberty under influence of pituitary gonadotropins.
Describe the duct system
Seminiferous tubules --> Straight tubules --> Rete testis --> Efferent ductules --> Epididymis --> Ductus (vas) deferens
What two things occurs to spermatozoa in the epididymis?
1. Acquire motility during passage through epididymis
2. Acquire surface associated proteins that will ultimately be removed in the female reproductive tract
What is benign prostatic hyperplasia (BPH)/BP hypertrophy?
Enlargement of the prostate
Hyperplasia - increase in the NUMBER of cells
BPH is linked to DHT which is formed by the action of 5alpha-reductase on testosterone
What are the three zones of the prostate?
- Surrounds urethra proximal to ejaculatory duct
- Accounts for 5-10% of glandular tissue of prostate
- Enlargement of this zone --> BPH
- 20% of prostatic cancers
- 25% of glandular tissue
- 5% of prostatic cancers
- 70% of glandular tissue
- 70% of prostatic cancers
What is capacitation of spermatozoa?
Glycoprotein coat and seminal proteins that overlie the acrosome are removed to enable spermatozoa to fertilize egg
1. Binding of sperm to zone pellucida
2. Acrosome reaction
3. Penetration through zone pellucida
4. Fusion of plasma membranes
5. Sperm nucleus enters egg cytoplasm
Genetic Sex Determination: X & Y chromosome
SRY gene that encodes TDF on Y chromosome
AR on X chromosome