Long before you had ever heard the word, “penis”, you were well acquainted with what has been called, “man’s favorite organ.” Boys discover their external sex organs in infancy. As they mature, their sex organs continue to develop as their understanding of the male reproductive systems also grows.
There’s more to it than what you see. Although most of the male reproductive organs are external, it’s important to understand how all your sex organs—external and internal—work together.
Let’s start with the obvious:
There are four major components that make up the exterior part of the male reproductive system (click on any one for more information):
The penis is the most visible part of the male sexual anatomy. It is made up of two parts, the shaft and the glans (also called the head). The shaft houses the corpora cavernosa (two flexible cylinders comprised of erectile tissue that run the length of the penis and support erections), and the corpus spongiosum (erectile tissue surrounding the urethra). When a man reaches sexual climax, he ejaculates a thick fluid (semen) through the urethral opening at the tip of the penis into the vagina. The semen carries sperm cells through the vaginal canal to the uterus where the sperm seek out the female egg for fertilization. Also, when a man urinates, the flow leaves his body through the urethral opening.
The urethra is a duct, or tube, that transports fluids from the inside of the body to the outside. In both men and women, the urethra is connected to the bladder and is used to pass urine out of the body. In males, however, the urethra is also connected to the “accessory glands,” which produce semen, and to the vas deferens, the duct that brings the sperm from the epididymis.
The testicles are located below the penis and begin producing male sex cells called sperm and testosterone, the male sex hormone after puberty. A man’s sperm production, once started, continues throughout his life; sexually mature males produce millions of sperm cells each day.
The interior part of the system is comprised of (click on each for more information):
The epididymis stores the sperm after the testicles produce them.
The vas deferens is a duct that carries sperm from the epididymis to the urethra.
There are several glands that work together to produce semen, or seminal fluid. The seminal vesicle produces a fluid that provides energy to the sperm as they seek out the female sex cell, or the egg. The prostate gland makes a different fluid that helps the sperm move more quickly through the female reproductive system. Another set of glands, called bulbourethral or Cowper's glands, makes a small quantity of fluid that helps protect the sperm on its way through the urethra by neutralizing any leftover traces of acidic urine. Sperm can live inside the female reproductive system for up to 48 hours, and seminal fluid helps the sperm move around and stay nourished.