lecture 11 - spermatogenesis

all structures sperm pass through

• seminiferous tubules → straight → rete → efferent ductules → epididymis → vas deferense → ej. duct → urethra (3 parts) → exit

semen/purpose of semen?

• normal volume = ~2-3+ milliliters

  • 20 million + sperm/ml

• established norms for pH, viscosity, sperm characteristics, etc

  • nutrients

  • protection

  • combat female reproduction tract → acidic, viscosity

  • transport

components of semen

correct order of hormones from hypothalamus to testes?

• GnRH → LH/FSH → testosterone

spermatogenesis vs spermiogenesis

• spermatogenesis = formation of sperm cells

• spermiogenesis = maturation of sperm

spermatogenesis

• formation of spermatids

• takes place in the seminiferous tubules

• begins at puberty and doesn’t stop (unlike ovulation)

  • sperm count declines with age/lifestyle choices

• one production cycle = ~64 days

  • a new cycle begins every ~16 days

spermatogenesis — IMP components of seminiferous tubules

• germ cells → least mature cells

  • singular = spermatogonium, plural = spermatogonia

  • the stem cells of the testes

• myoid cells → smooth muscle

• sertoli cells

• leydig cells

sertoli cells

• AKA sustentacular or nurse cells

• promote sperm production — stimulated by FSH

• form blood-testis barrier

1. prevent interaction with bloodborne substances

2. immunological privilege

3. tightly control environment

Leydig cells

• AKA teticular interstitial cells

• located between the seminiferous tubules

• help maintain spermatogenesis via testosterone production —- stimulated by LH

• mostly active during puberty onward

spermatogenesis — process outline

spermatogenesis — sperm cell development

spermatogenesis — role of FSH and LH