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628 SectioN iii RepRoductive ` REPRODUCTIVE—ANATOmy RepRoductive ` REPRODUCTIVE—PHySIOlOgy
Seminiferous tubules
CEll FUNCTION lOCATION/NOTES
Spermatogonia Maintain germ cell pool and produce 1° Line seminiferous tubules A
spermatocytes Germ cells
Sertoli cells Secrete inhibin B inhibit FSH Line seminiferous tubules
Secrete androgen-binding protein maintain Non-germ cells
local levels of testosterone Convert testosterone and androstenedione to
Produce MIF estrogens via aromatase
Tight junctions between adjacent Sertoli cells Sertoli cells are inSide Seminiferous tubules,
form blood-testis barrier isolate gametes Support Sperm Synthesis, and inhibit FSH
from autoimmune attack Homolog of female granulosa cells
Support and nourish developing spermatozoa
Regulate spermatogenesis
Temperature sensitive; sperm production and temperature seen in varicocele,
inhibin B with temperature cryptorchidism
Leydig cells Secrete testosterone in the presence of LH; Interstitium
testosterone production unaffected by Endocrine cells
temperature Homolog of female theca interna cells
Leydies (ladies) dig testosterone
– HYPOTHALAMUS
GnRH
Anterior
pituitary
Spermatogonium
– – Inhibin B Spermatocyte
FSH Sertoli cell Spermatids
LH Spermatozoon
A
Leydig cell
Androgen-
binding protein
Testosterone
Capillary
Sertoli cell
nucleus
Lumen of
seminiferous tubule
SPERMATOGENESIS
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