Spermatogenesis Flashcards
What are the stages of spermatogenesis?
Primordial germ cells (2N)
Spermatogonia (2N)
-meiotic cycle
Primary Spermatocytes (2N) -meiosis 1: first maturation division
Secondary spermatocytes - 2 cells
-second maturation division, meiosis II
Spermatids - 4 cells
What is spermiogenesis?
Maturation of spermatids into mature sperm cells
4 phases:
- Golgi phase:
- Cap phase:
- Acrosomal phase:
- Maturation phase:
Golgi Phase of spermiogenesis
- Golgi phase: proacrosomal vesicles, acrosomal vesicles
Cap phase of spermiogensis
- Cap phase: mature acrosome forms a cap over the nucleus
Acrosomal phase of spermiogenesis
- Acrosomal phase: rotation of sperm, acrosomal pole faces wall of seminiferous tubule. Cytoplasm pushes off as a residual body
Maturation phase of spermiogenesis
- Maturation phase: completion of flagellum and nuclear condensation
What about sperm DNA allows it to supercompact?
Special histones, proamines
Where are Sertoli cells?
Aka: sustentacular cells
Immunological barrier between the forming sperm cells and the rest of the body and spematogonia (germ cells)
They form the blood-testes barrier. distributed throughout the periphery of the seminiferous epitheliom
What are the functions of Sertoli cells?
Physical support and maintence
Maintain and coordinate spermatogenesis
Secrete estrogen, inhibin and anti-mullarian factor
-convert testosterone to estrogens
Maintain the blood-testes barrier
Phagocytize residual bodies of sperm cells
What role does testostrone play in relation to the blood-testes barrier?
Stimulates the formation of a new blood-testes barrier closer to the basal lamina
End of the spermatogenesis process where spermatogonium is seperated from the res of the process by blood-testes barrier. As the spermatogonium begins to mature into a spermatid it crosses that barrier. Late spermatids are bound to the apical side of the serotoli cell and when mature those suface adhesion complexes and tight junctions are broke down allowing developing spermatocyte closer to the lumen. Testostrone formulates the new blood-testes barrier
What is LH’s role in sperm production in the male reproductive system?
Secreted by the anterior pituitary and binds to it’s receptor on interstitial cells of Leydig
Leydig cells synthesize testostrone from cholestrol
Testrostrone goes onto sertoli cells, the prostate, seminal vescle, epididymis, ductus deferens, penis and strotum.
How is immotile sperm transported throug the male reproductive tract?
Passive transport by testicular fluid
Smooth muscle contractions
Cilia in seminiferous tubules
Pathway: rete testis, efferent ductules, head of epididymis
Where does sperm mature? How long does that take?
Sperm matures in the head of the epididymis and it takes about 12 days
Fluids are added to the sperm as it travels the ductus deferens by the seminal vescles and prostate, whats in the fluids?
“Semen” is composed of fuctose and protaglandins from the seminal vescles and citric acid, Zn, Mg and phosphatase from the prostate
What’s the pH in the upper vagina? What’s the optimal pH for sperm? How does seminal fluid change vaginal pH?
pH of upper vagina: 4.3
Semen changes it momentarily to 7.2
Optimal pH for sperm: 6.0-6.5 (also pH of the cervix)
