Reproductive system

Male reproductive system

Testicles

The testicles are paired organs, normally four to five centimeters long, located within the scrotum (a multi-layered muscular structure that protects the testes and helps with temperature regulation). The testicles have two very important functions, and each of them is essential for normal male fertility:

Production of testosterone
Production of sperm

After sperm develop they move from the testicles to the epididymis.

Epididymis

The epididymis is a long, narrow tube, approximately six meters in length, which is coiled and contained beneath a fibrous sheath. The epididymis sits on the back of the testis, and it is divided into head, body and tail regions. From the epididymis, sperm proceed into the vas deferens.

Vas deferens

The vas deferens is also a long, tube-like structure that connects the epididymis to the urethra (the tube that expels sperm). During ejaculation, sperm stored in the epididymis are released through the vas deferens and into the urethra.