A tough, fibrous membrane, the tunica albuginea, covers the testes, extending inward to form fibrous partitions or septa, dividing them into internal compartments called lobules. Each lobule has 1 to 3 tightly coiled seminiferous tubules where sperm production occurs. These tubules merge into a tubular network at the back of the testis, known as the rete testis. It connects to 15 to 20 efferent ductules, leading to the epididymis.

The spermatogenic cells, responsible for producing sperm, are arranged in layers along the walls of the seminiferous tubules. They differentiate with support and nourishment from Sertoli cells to form mature sperm towards the lumenal end. Between the adjacent seminiferous tubules are interstitial cells, also known as Leydig cells. These cells are essential in producing androgens, including testosterone, the primary male sex hormone.

The testicles receive oxygenated blood through long testicular arteries. A network of veins, called the pampiniform plexus, surrounds these arteries. These veins are responsible for draining the deoxygenated blood from the testicles and absorbing heat from the incoming arterial blood. This process ensures that the testicular tissue is optimally nourished and maintained at the correct temperature for healthy sperm production. Deviation from the optimal temperature range can disturb the delicate process of sperm production, leading to a decrease in fertility. As a result, it is crucial to maintain the correct temperature for the testes to function correctly.