Testis and Epididymis

Testis
The testis produces sperm and sex hormones. Both testes are suspended in the scrotum by fibrovascular stalk, the spermatic cord. The left testicle is often hanging lower than the right. Scrotum serves for regulating a lower than body temperature for the testes, ensuring proper spermatogenesis. Mature testis is approximately plum-shaped, 4-5.5cm long. In its usual position in the scrotum, it has a wider margin pointing posteriorly and a narrower margin pointing anteriorly. At its posterior border, the mediastinum testis, also called rete (net) testis, contains the blood vessels, nerves and ductus deferens, that enter and leave the epidididymis with the spermatic cord. Internally, the testis is arranged into lobules, which are divided by fibrous septa. Each lobule contains highly coiled seminiferous tubules, where spermatogenesis takes place. The seminiferous tubules are then joined by straight tubules to the rete testis (i.e.: testicular network).

Vasculature & Innervation

 * Arterial supply: by the testicular arteries.
 * Venous drainage: by the pampiniform venous plexus, which in turn drains into testicular vein; it is a network of 8-12 veins lying anterior to the ductus deferens and surround the testicular artery in the spermatic cord. They play an important role in the thermoregulation of the testis.
 * Lymphatic drainage: follows the testicular artery and vein to the right and left lumbar and preaortic lymph nodes.
 * Innervation: Autonomous nerves of testis arise from testicular nervous plexus on the testicular artery, containing parasympathetic and visceral afferent fibers and sympathetic fibers from T7.

Epididymis
It is an elongated structure on the posterior surface of the testis. The efferent ductules of testis transport newly developed sperms to the epididymis from the rete testis. It is formed by minute convolutions of the duct of epididymis, which is the very beginning of the ductus deferens. These convolutions are so tightly compacted that they appear solid. It is composed of 3 parts:
 * 1) Head of the epididymis: the superior, expanded part, that is composed of lobules formed by the coiled ends of 12-14 efferent ductules.
 * 2) Body of the epididymis: consists of the convoluted duct of the epididymis.
 * 3) Tail of the epididymis: continuous with the ductus deferens.