REPRO - Male Flashcards
(35 cards)
What is the normal volume of the testes, measured using?
- 15-25ml
- Orchidometer
Where in the testis does spermatogenesis occur?
-Semineferous tubules
Sperm develop between the Sertoli cells, what happens to the spermatogonium (1ry germ cells) at the inner edge of the tubule?
- They divide by mitosis to increase in number lots
- Some commit to meiosis to develop into sperm, and enter lumen to rete testis-epidid-release
What do the leydig cells outside the tubule produce?
Testosterone
What type of cell are Sertoli Cells?
Tall, columnar endothelial cells that make up the wall of the sn. tubules
What makes the adluminal compartment in the sn lobule?
-tight junctions between sertoli cells that keep developing sperm in confined compartments
The luminal compartment, interstitial space on outside and adluminal compartment form what immunity structure?
- blood-testis barrier
- so immune system never contacts gametes
What may compromise the blood-testis barrier leading to subfertility?
-Vasectomy as testis leaks into circulation, antibodies against own sperm
What are A vs B spermatogonia?
A divide mitotically to replenish themselves
B are commited to meiosis
Spermatogenesis goes through a new cycle every 16 days, how many days does the process take
apporx 74
What are the 3 stages of spermatogenesis?
- mitotic proliferation of spermatogonia
- meiosis and development of spermatocytes
- spermiogenesis, elongation, loss of cytoplasm
Each cell division of a spermatogonium makes an incomplete spermatid, -how?
-cells remain connected to each other by cytoplasmic bridges forming a syncytium allowing synchronous development
LH binds to Leydig cells which makes testosterone which circulates peripherally bound to what?
ABP - androgen binding protein
What effect does FSH have when binding to Sertoli Cells?
maintains their population and converts androgens to oestrogens via aromatase
Why do anabolic steroids cause testicular atrophy?
-Neg feedback on hypothal so less FSH
What 3 changes occur to make an erection?
- cavernosal arteries dilate so BF increases
- venous return of penis constricts
- higher BP in c.cavernosum
approx 120million sperm in ejaculate of 1.5-6ml. Which part of the ejaculate is the most sperm rich?
-The initial part of the ejaculate
In the vas defs, the small amoun of sperm in the epidymal fluid is mixed with other secretions from where to make “seminal fluid”? 3
- seminal vesicles
- prostate
- bulbourethral gland
What is the bulbourethral glads clear viscous secretion AKA? 2 Functions?
- Pre-ejaculate
- rich in salt
- lubricates urethra for spermatozoa to pass
- neutralises traces of acidic urine
What 5 things are in the seminal vesicle secretions which join at the ejac. duct? This makes up 50-70% of ejaculate. pH = high (protects vs acidic vagina)
- proteins
- enzymes
- fructose
- mucus
- vit C
- prostoglandins
The prostate contributes 30% of ejaculate. What 4 things are in this milky fluid and why?
-proteolytic enzymes
-prostatic acid phosphotase
-prostate specific antigen (PSA)
Liquefaction/more runny
-high zinc conc
What is the acrosome of the mature spermatazoom for?
-bursts near egg and enzymes cut through the outer layer of the egg
What is capacitation (reason a fresh ejaculated sperm cant fertilise an egg)?
-4-18hr time requirement for acrosome properties to change as you dont want it bursting before it reaches egg
What coagulates the ejaculated sperm and why?
- the prostatic and seminal vesicle secretions
- so semen stays together and helps target ejaculate to cervix entrance
