the dreaded repro. Flashcards
describe the covering of the testes.
tunica alberguinea is a thin fibrous semi-covering. tunica vaginalis (viceral) then tunica vaginalis (parietal) then internal spermatic fascia, cremaster fascia, and external spermatic fascia.
why is thermoregulation required?
optimum temp for spermatogenesis is 35 degrees so heat is transferred from the testicular arteries to the pamniform plexus of veins.
what is spermatogenesis?
differentiation of spermatids to spermatozoa. there is a loss of cytoplasm and a tail forms.
describe the full maturation of sperm from spermatogonium to spermatozoa.
spermatogonium differentiate into type A or type B spermatogonia. type A continue to produce daughter cells and do not pass through the blood testes barrier. and do not differentiate further. type B differentiates into a primary spermatocyte and then divides to form secondary spermatocytes. these then divide to form spermatids. these spermatids then undergo spermatogenesis to form spermatozoa.
what is the function of sertoli cells?
they form the blood-testis barrier, they are supporting cells for the sperm and they remove debris etc.
what is the acrosome?
acts as a spermatic head. releases acrosomal enzymes in the breakdown of the zone pellucida
why are mitochondria needed?
flagellar movement.
what are the other parts of a mature sperm?
axoneme = cytoskeletal structure. the principal piece is the bulk of the tail and it is the axoneme surrounded in a membrane. the end piece is bare axoneme
describe the drainage of the testes.
the seminiferous tubules join together to form the rete testes. the rete testes drain into the 12 small ducts and they drain into the epididymus.
how long can the epididymus hold sperm for? what is its histology?
40-60 days. long columnar epithelium with a prominent brush border
describe the anatomy of the vas deferens.
30cm muscular tube. shorter columnar epithelium. peristalisis. widens at its terminal called the ampulla.
what is normal sperm count? what is infertility?
50/100 mil.
how many sperm are made per minute?
300-600
how long does spermatogenesis take?
64 days.
what gene determines sex?
SRY
in the absence of Y, how does the foetus develop?
the wolffian duct regresses in the absence of testosterone. Oestrogen production stimulates the differentiation of the mullein duct. the mullerian duct forms the cervix, the uterus, upper vagina, and the fallopian tubes.
when does differentiation begin?
6 weeks