Emergency Ultrasound > Introduction > Physiology

Physiology

The testes are composed of 90% seminiferous tubules (Sertoli and germ cells) and 10% interstitial (Leydig Cells, connective tissue, blood supply)

2 major functions of the testes:

I. Spermatogenesis occurs in the Seminiferous Tubules, takes approximately 70 days to complete, occurs continuously and is regulated by FSH, LH.

• Seminiferous tubules
• Rete testis
• Epididymis – storage and maturation of sperm
• Vas/ductus deferens

3 major phases

• Mitosis Spermatogonia (germ cells) _ Spermatocytes
• Meiosis Spermatocytes (2n) _ Spermatids (1n) haploid like mature sperm
• Spermiogenesis spermatids _ mature sperm (sheds cytoplasm, acrosome forms, etc)

Sertoli Cells have supportive function in providing nutrients to developing sperm cells, tight junctions to provide blood-testis barrier and secrete aqueous secretion into the lumen to aid sperm transport

II. Biosynthesis of Testosterone (T) – Leydig Cells

Testosterone is synthesized from Cholesterol

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