Male Reproductive System: Testes

• The male reproductive system consists of a pair of testes, a system of genital ducts, accessory sex glands, and a copulatory organ (the penis).

Testes

• Testes produce male gametes called spermatozoa.
• Testes perform an endocrine function and secrete testosterone, the primary male sex hormone.
• Each testis is covered by a thick capsule of dense, fibrous connective tissue, the tunica albuginea.
• Tunica albuginea is thickened along the posterior wall of the testis, projecting inward as the mediastinum testis.
• Blood vessels and lymphatic vessels, along with channels carrying spermatozoa, pass through the connective tissue of the mediastinum testis.
• Fibrous septa, or septula testis, arise from the mediastinum testis and penetrate the substance of the testis, dividing it into 250-350 pyramidal compartments: the testicular lobules.
• Beneath the tunica albuginea is a layer of loose connective tissue containing networks of blood vessels: the tunica vasculosa, which also lines the septula testis.
• Each testicular lobule contains 1-4 highly coiled seminiferous tubules, the site of male gamete production.
• Seminiferous tubules are surrounded and supported by loose intertubular connective tissue.

Seminiferous Tubules

• Seminiferous tubules produce and transport sperm cells inside the testes.
• A seminiferous tubule measures about 200 µm (0.2 mm) in diameter and approximately 50 cm in length.