The Male Reproductive System

The Male Sex Organs

The male reproductive system is almost entirely external. The penis consists of the urethra, the shaft, a number of sensitive nerve endings, and the glans, also known as the head of the penis, which is covered with the foreskin, a loose layer of skin often surgically removed in a procedure known as circumcision.

The Male Reproductive SystemTesticles (testis singular, testes plural) are the male gonads, the organs that produce sperm. Most men have two testes, which are suspended from the body by the spermatic cord and rest inside the scrotum, a sac that hangs under the penis. Divided internally into two pouches by a thin membrane, the scrotum is covered by an outer layer of thin, wrinkled skin which in turn covers a layer of muscle, which acts as a protective covering and serves to maintain the testicular temperature at about 2 degrees below abdominal temperature.


The Male Reproductive SystemSperm is produced in the testes, then travels through the vas deferens, seminal vesicles and prostate; en route, it picks up testosterone, seminal fluid and prostate fluid, all of which combine to form semen. When a man experiences sexual arousal, the penis fills with blood and becomes erect. At climax, semen, filled with several million sperm, shoots from the urethra and tries to fertilize an egg. If the sperm is successful, a fetus forms over the next several months. If not, it's no big deal for the reproductive system--it produces several billion sperm a day!