Production of normal sperm cannot occur at the body temperatures of most mammals. So the testes are held outside the abdominal cavity in the scrotum, where the temperature is lower than in the abdominal cavity.
From the seminiferous tubules of a testis, mature sperm pass into the coiled tubules of the epididymis.
During ejaculation, sperm are propelled through the muscular vas deferens and the ejaculatory duct, and then exit the penis through the urethra.
Semen is composed of sperm plus secretions from three sets of accessory glands.
The two seminal vesicles contribute about 60% of the total volume of semen.
The prostate gland secretes its products directly into the urethra through several small ducts.
The bulbourethral glands secrete a clear mucus before ejaculation that neutralizes acidic urine remaining in the urethra.
The human penis is composed of three cylinders of spongy erectile tissue.
During sexual arousal, the erectile tissue fills with blood from the arteries, causing an erection.
The head of the penis has a thinner skin covering than the shaft, and is more sensitive to stimulation.
Gametogenesis = the production of gametes by meiosis. This differs in females and males
Sperm are small and motile and are produced throughout the life of a sexually mature male.
Spermatogenesis is production of mature sperm.
Cross section of seminiferous tubule
Sertoli cell nucleus
Primordial germ cell in embryo
Spermatogonial stem cell
Lumen of seminiferous tubule
Spermatids (at two stages of differentiation)
Differentiation (Sertoli cells provide nutrients)