spermatogenesis Flashcards
spermatogenesis (whats the basic scheme)
spermatogonium (diploid, 2N, 2C) stem cell → [Interphase] → primary spermatocyte (diploid, 2N, 4C) → [Meiosis I] → secondary spermatocyte (haploid, 1N, 2C) → [Meiosis II] → spermatid (haploid, 1N, 1C)
what are the three phases of spermatogenesis
proliferative
meiotic
spermiogenic
what goes down in the proliferative phase of spermatogenesis?
spermatogonia –> spermatocytes
spermatogonial cells (type Ad, Ap, B)
Ad –> differentiate into Type Ap
Ap –> divide by mitosis, give rise to type B
B –> divide to produce preleptotene spermatocytes that can enter meiosis
what happens in the meiotic phase of spermatogenesis?
spermatocytes undergo meiosis (2C–> 1C)
what happens in the third and final spermiogenic phase of spermatogenesis?
spermatids undergo morphological change and mature into spermatozoa
what is spermiogenesis?
spermatids (haploid 1n, 1c) –> mature spermatozoon (haploid 1n, 1c)
What are the four stages of spermiogenesis?
golgi
cap –> allow sperm to penetrate egg corona
acrosomal
maturational
where does post testicular sperm maturation occur?
epididymis, where they develop motility and become capable of fertilizing
where does spermatogenesis occur?
seminiferous tubules
-makes up 80% of total testis
what cell types maintains the blood testis barrier?
sertoli
what are spermatogonia?
maintain germ pool and produce primary spermatocytes
line seminiferous tubules
what do sertoli cells secrete?
- inhibin, which has negative feedback on FSH
- androgen binding protein –> maintins local levels of T
- MIF
what cells are reponsible for mintaining the blood-testis barrier?
sertoli cells via tight junctions
are sertoli cells temperature sensitive? are leydig cells?
yes. decreased sperm production and inhibin at increased temperature
leydig cells are not temp sensitive
