ANHB2214 Study Guide - Midterm Guide: Spermiogenesis, Sexual Differentiation, Corpus Spongiosum Penis
3 Jun 2018
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Male Reproductive System:
• Testis
o Function
▪ Produce the gametes (spermatogenesis)
▪ Produce androgens (steroidogenesis)
o Covered by a collagenous capsule → tunica albuginea
o Tunica vascuolsa penetrate into tesis
o Mediastinum/hilum → where blood vessels/tubes enter and leave
o Septum divide testis into lobules → 200-300 lobules per testis
o Within lobules → coiled tubes → seminiferous tubules
o Ductuli efferentes take tubules out of testes into epididymis
• Seminiferous tubules
o Originate from mediastinum and branch out → 1-4 in each lobule
o Lined by seminiferous epithelium → undergo differentiation to
form sperm
o Supported by peritubular tissue
o Base → fibroblasts and basal lamina
o Germ cells (spermatogonia) start at base of tubule
o As these cells develop, they move up until they are released into
the lumen
• Sertoli cells
o Sit against wall of tubule
o Tall columnar cells
o Extend from basement membrane to lumen of tubule
o Prominent nucleolus
o Tight junctions formed between neighboring Sertoli cells →
creates blood-testis barrier
o Function
▪ Support, protection and nutritional regulation of
developing spermatozoa
▪ Phagocytosis of residual bodies released from spermatids
▪ Secretion of testicular fluid into lumen of tubule
▪ Production of androgen-binding protein (ABP)
▪ Secretion of inhibin
• Leydig cells
o Differentiate and secrete testosterone
o Sits in interstitial compartment
o Round, central nucleus
o Can have lipid drops → cholesterol
• Spermatogenesis
o Process whereby spermatogonia develop into sperm
o Spermatogonial phase
▪ Spermatagonia against wall of seminiferous tubule
▪ Type A → undergo regular mitotic divisions to build up
population
▪ Type B → recruited for spermatogenesis
o Spermatocyte phase
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