Male Reproductive System

Learning Outcomes

  • Describe structures/functions of male reproductive system.

  • Label diagrams of male reproductive organs.

  • Name/described associated glands.

  • Summarize actions of male gonadotropin hormones and testosterone in reproduction.

Male Reproductive System

  • Primary sex organs: testes (produce gametes).

  • Secondary sex organs: ducts, glands, penis (store, convey sperm).

External and Internal Genitalia

  • External: Penis, Scrotum.

  • Internal: Testes, Epididymis, Ductus Deferens, Seminal vesicles, Prostate gland, Bulbourethral glands.

The Scrotum

  • Contains testes; divided into left/right compartments.

  • Regulates temperature for optimal sperm production (35°C).

  • Temperature regulated by Cremaster, Dartos, and Pampiniform muscles.

The Testes

  • Anatomy: oval, 4 cm long, covered by tunica vaginalis, tunica albuginea.

  • Seminiferous tubules: site of sperm production, lined with germinal epithelium.

Seminiferous Tubules

  • Contain germ cells and Sertoli cells (support germ cell development).

  • Sperm partially mature in rete testis.

Spermatic Ducts

  • Sperm travels through: Efferent ductules → Epididymis (maturation) → Ductus deferens → Ejaculatory duct (into urethra).

Accessory Glands

  • Seminal Vesicles: 60% of semen.

  • Prostate Gland: 30% of semen, what surrounds urethra.

  • Bulbourethral Glands: produce lubricating fluid during arousal.

The Penis

  • Composed of root, shaft, glans; serves in semen deposition.

  • Contains erectile tissues: Corpus spongiosum (ventral) and Corpus cavernosum (dorsal).

Anatomy of Mature Sperm

  • Contains Acrosome, Nucleus, Midpiece, Principal tail piece.

Semen

  • Fluid expelled during orgasm (2-5 mL); contains 50-120 million sperm/mL.

  • Prostate: thin fluid with ions, enzymes.

  • Seminal Vesicles: viscous fluid with fructose, prostaglandins, and proteins.