Anatomy of the penis : Penis enlargement

This section contains an overview of the structure and function of the penis. It is designed to give you a greater understanding of what those medical terms mean when used by doctors in relation to the penis. Plus it will increase your understanding of how the penis works.

Penis and the male reproductive system

The penis, along with the testicles and scrotum are found outside of the body and together, they form part of the male reproductive system. It contains many tactile sensory receptors or nerve endings which respond to all forms of external stimulation. The penis is the most sensitive part of the male anatomy.

The penis itself consists of three parts:

• Shaft
• Root
• Glans

The shaft or body of the penis is tubular shaped and contains three chambers. These chambers are comprised of a soft, spongy tissue which houses numerous large spaces. These spaces fill with blood when the man becomes sexually aroused.

This causes the penis to stiffen and become erect. It also means that it is able to penetrate the woman’s body during sexual intercourse.

The root is the part of the penis which attaches it to the abdomen.

The glans is the characteristic cone shape of the head of the penis. It is covered by loose skin called the ‘foreskin’ and contains the urethra – a thin tube which connects the bladder to the outside of the body. This transports both semen and urine in men.

Semen is expelled (ejaculated) from the glans of the penis during male orgasm. Urine flow is blocked during this time which enables only semen to leave the urethra.

The scrotum is the pouch-like structure which hangs behind the penis. It contains the testicles plus nerve and blood vessels and is designed to protect these. It also controls the temperature of the testicles to enable sperm to develop and flourish. In order for this to happen, the temperature of the testicles needs to be slightly cooler then normal body temperature. The testicles or testes are two, oval shaped organs which are fastened within the scrotum by the spermatic cord. They produce sperm and the male sex hormone testosterone.

Behind each testicle rests the epididymis. This acts as a storage and transport system for sperm which has been produced via the testicles. Sperm is transported from here into the vas deferens during sexual arousal. The vas deferens or to be more precise the ‘vasa deferentia’ are two slim tubes which transport sperm from the testicles to the penis. These tubes are cut or snipped during a vasectomy as a form of permanent birth control.

For more information, visit our complete guide to vasectomy.

The penis, testicles and scrotum are external organs of the male reproductive system. Internal organs of this system include:

• Prostate gland: small, walnut shaped gland located below the bladder and in front of the rectum. Contains fluids which help to nourish sperm as well as contributing to the ejaculatory fluid.
• Vas deferens: see above.
• Urethra: this tube runs from the bladder to the glans and enables semen to be expelled from the body during climax.
• Ejaculatory ducts: a combination of the seminal vesicles and the vasa deferentia. They act as a conduit into the urethra.
• Seminal vesicles: small sacs that are attached to the vas deferens at the bottom of the bladder. They produce a fluid which energises the sperm and so aids with their movement.
• Bulbourethral glands: also known as ‘Cowper’s glands’. These tiny, pea-like structures are found on the outside of the urethra, below the prostate gland. They produce a clear fluid which empties into the urethra: that acts as a lubricant as well as neutralising any traces of acidity.

This is a brief overview of the penis: how it works and its role within the male reproductive system.