Penis is the male sexual organ. It consists of the root, body, dorsum, urethra and glans. The glans is covered with thin skin called the prepuce or the foreskin. The penis is used for urinating, since the urethra passes through it. Another function of the penis is erection and ejaculation, which are essential parts of a complete sexual intercourse. Erection is the hardening of the penis which results from a sexual excitation. Ejaculation is an eruption of the semen during the climax or the orgasm. A sexual intercourse is not the only occasion on which the ejaculation occurs. A nocturnal emission is such a case. During the nocturnal emission the semen is ejaculated while the person is asleep. It is typical for pubertal boys. The length of the penis is very individual. On average it is 6.8-10.7 cm in the rest an 11.8-15.9 cm during the erection. It is often believed that its length correlates with the size other bodily parts such as the foot, hand or nose. However no study has shown such correlation. It is also interesting that the penis originates from the same primitive structures as the clitoris and therefore exhibits many similarities in the structure and certain functions.
The penis consists of erectile bodies. They are three, they resemble a sponge and contain the urethra, vessels and muscular tissue. During the sexual stimulation the blood vessels fill these sponge-like bodies with blood, which leads to erection. The erectile bodies increase their volume and prevent the free drainage of the blood from the penis. It therefore hardens an enlarges. We can rarely encounter a damage of the erectile bodies such as their fracture. The damage usually results from wild or unconventional sexual practices. When the fracture occurs, we can hear a click and bruises form immediately. They can also spread onto the abdomen. The penile fracture is very painful and doctor’s help should be sought immediately.
Penis and Sex
Although the terminal part of the urinary system, the urethra, passes through the penis, the prime role of the penis is in the sexual intercourse. An erection is the basic precondition for the sexual intercourse. The erection is a hardening of the male sexual organ, the penis, during which stands up and enlarges. The hardening is a prerequisite for entering the vagina. The mechanism of the erection of the erectile bodies consists of their filling with blood, which results from a sexual arousal. The erection can be induced by erotic imagination in the brain, by a stimulation of the touch receptors on the surface of the glans and other erogenous zones. So called erection center is situated in the sacral portion of the spinal cord. This centre can be modulated by the brain. The modulation can be positive (erotic imagination) or negative (fatigue, stress,…). When a certain threshold of arousal, which is hugely individual, is reached, the ejaculation occurs. Ejaculation is a fast eruption of the semen from an erected penis. It occurs in several quick waves. An ejaculation usually arises during an orgasm, but the semen can also be ejaculated during a sleep. After the ejaculation the blood flow into the penis is suddenly decreased and the blood accumulated in the erectile bodies can be drained and the resting state in restored. During the sexual intercourse the male reproductive cells, the sperms are put into the woman’s body. In the fallopian tube one sperm then merges with the female reproductive cell, the ovum. The fertilized egg than develops furthermore and give rise to a new individual. Good erectile function and subsequent ejaculation is an indispensable precondition for a natural conception.
Diseases of the penis
The penis can be affected by numerous diseases. These are the most common ones:
- Penile cancer
- Phimosis or a narrowing of the prepuce, which prevents its smooth retraction over the glans
- Erectile disfunction, defined as an inability to reach or stay in erection
- Priapism or a long lasting erection, often accompanied with a significant pain