The testes are located in the scrotum, which keeps them outside the body. This is important because optimal sperm temperature is about 95 degrees Fahrenheit, whereas normal body temperature is 98.6 degrees.
Inside each testis are hundreds of seminiferous tubules surrounded by connective tissue and interstitial cells. The interior tubule network connects with the epididymis, which sits on top of each testis.
The seminiferous tubules are where sperm cells are created, although they are immature until they are passed into the epididymis.
The interstitial cells produce androgen hormones such as testosterone, a defining male sex hormone.
Because the testes are outside the body, they are more vulnerable to blunt trauma. Blood vessels can constrict a testis (torsion), and sometimes interstitial cells do not produce enough testosterone (hypogonadism). Testicular cancer is an extremely serious condition. See Resources for more information.