The Testicles

Function of the Testicles

There are two main types of cells that allow the testicles to produce sperm and hormones: germ cells and supportive stromal cells.

Germ cells line the seminiferous tubules and produce sperm. The tubules also contain a type of stromal cell called Sertoli cells, which help the germ cells produce and transport sperm.

Sperm travel through the long maze of the seminiferous tubules and rete testis, ending up in the epididymis, where they fully mature over the course of a few weeks.

Once they are mature, sperm move to the vas deferens, where they combine with fluids from the nearby prostate gland and seminal vesicles, forming semen.

During ejaculation, the sperm-carrying semen is pushed out of the body through the urethra in the penis.

Aside from Sertoli cells, there are various other types of stromal cells that serve different purposes.

Leydig cells — specialized stromal cells — are located within the soft connective tissue in between the seminiferous tubules, beneath the tunica albuginea, and in the septum tissue that divides the scrotum into two areas.

These important cells are the body’s main source of testosterone.

As a male sex hormone, testosterone helps the germ cells make sperm and is vital to the development and function of the male reproductive organs.

In addition, testosterone gives men libido (sex drive).

Testosterone is also responsible for producing secondary sex characteristics in men, such as a deep voice, body and facial hair, and enlarged muscles and body size.