# Testes --- The **testes** (singluar: **testis**) is the primary organ of the [[male reproductive system]]. As a gonad, it is the site of [[gamete]] reproduction—for males this is the [[sperm]]. ![[testes.png]] ## Anatomy The testes are attached to the rest of the body by the **spermatic cord**, which contains [[blood vessels]] [[nerves]], and part of the **vas deferens**. They are surrounded and protected by a [[serous membrane]] called the **tunica vaginalis**. The testes are internally divided into ~250 **lobules** by partitions called **septa**. Inside these septa are up to four **seminiferous tubules**, which are very long and thin, and convoluted. Each seminiferous tubule contains **sustentacular cells** and germ cells called **spermatogonia**. These spermatogonia become sperm through [[sperm|spermatogenesis]]. Squished in between the seminiferous tubules are the **interstitial cells**, which do many fun things like secrete [[testosterone]]. The seminiferous tubules all empty out into more centrally-located tubules called the **rete testis**, which then empty into the **epiddymis**, which covers the superior and posterior surfaces of the testes. Internally, the epididymis contains a very long, convolute duct that stores sperm until they are fully mature and motile. Mature [[sperm]] stay there until they're ejacutlated, when they exit out of another tube called the **vas deferens**, sometimes called the **ductus deferens**. These sperm cannot swim yet, so the vas deferens uses [[peristalsis]] to move them along. If they are not ejaculated in a few months, they die off and are resorbed by the cells of the duct of the epididymis. ## Physiology The ideal temp is 1-2 degrees lower than body temp, so the **dartos muscle** and **cremaster muscle** move the testes up and down (towards/away from the body) accordingly [[sperm|spermatogenesis]] ## Problems Related to the Testes [[testicular torsion]] ___