Physiology of Reproduction 2 Flashcards
Where does spermatogenesis occur?
Testis
Anteriorly, the testes are covered by a saclike extension of the peritoneum called what?
Tunica vaginalis
What is the tunica albuginea?
White fibrous capsule
Anatomy within the testes
Septa divide organ into compartments containing seminiferous tubules where sperm are produced
Leydig cells
Clusters of cells between the seminiferous tubules
Source of testosterone
Sertoli cells
Promote sperm cell development
Blood-testis barrier formed by tight junctions between sertoli cells (separates sperm from immune system)
Seminiferous tubules drain into network called
Rete testis
What divides the 2 compartments of the pendulous pouch holding testes?
Median septum
Where does meiosis occur?
Seminiferous tubules
Spermatogonia produces _ kinds of daughter cells
2
Where do type A spermatogonia reside?
Outside the blood-testis barrier and produce more daughter cells until death.
What type of spermatogonia differentiate into primary spermatocytes
Type B
Meiosis I produces
2 secondary spermatocytes
Meiosis II produces
4 spermatids
Spermiogenesis is transformation of spermatids into
Spermatozoa (sprouts tail and discards cytoplasm to become lighter)
300-600 sperm are made per gram of testis per __?
Second
How long does it take for completion of spermatogenesis?
64 days
Sertoli cells are stimulated by…
FSH
Leydig cells are stimulated by…
LH
What is the process for regulating spermatogenesis?
Hypothalamo-pituitary-testicular axis
Spermatozoon shape
Pear-shaped head.
whole structure = 4-5 microns long
Nucleus, acrosome, basal body of tail flagellum.
3 parts of tail = midpiece (mitochondria), principal piece (axoneme surrounded by fibres) and endpiece (axoneme, narrow tip)
Efferent ductules
12 small ciliated ducts collecting sperm from the rete testes and transporting it to the epididymis
Epididymis
6m long coiled duct adhered to posterior testis.
Where sperm mature and stored
Ductus vas deferens
45cm long tube passing from scrotum through inguinal canal to posterior surface of bladder. Widens into terminal ampulla.
Ejaculatory duct
2cm duct from vas deferens and seminal vesicle. Passes through prostate into urethra.
Constituents of semen
60% = seminal vesicle fluid
30% = prostatic
10% = sperm
Trace of bulbourethral fluid
Also contains fructose for energy for sperm motility
Fibrinogen
Clotting enzymes causing semen to clot
Prostaglandins stimulating female peristaltic contractions
What is a normal sperm count?
50-120 million/ml
(fewer than 25 million/ml associated with infertility)
