[ICD 10 Search]

Back
[ICD 10 Search]

Erection

This article discusses physiological erection. For erection of manmade structures, see construction.

An erection of the penisoccurs when engorgement of venous blood in two tubular structures at the bottom of the penis, the corpora cavernosa, results from a variety of stimuli. The corpus spongiosum is a single tubular structure located just above the corpora carvernonosa, and contains the male urethra, through which urine and semen pass during urinationand ejaculation, respectively. This may also become slightly engorged with blood, but less so than the corpora cavernosa. Penile erection usually results from sexual stimulation and/or arousal, but can also occur by such causes as a full urinary bladder or spontaneously, most commonly during erotic or wet dreams. An erection results in swelling and enlargement of the penis or the swelling of the female counterpart to the penis, clitoris. Erection enables sexual intercourseand other sexual activities, though it is not essential for all sexual activities.

In addition to sexual arousal, erection in males can be caused by mechanical stimulation, or by the pressure of the filled urinary bladder. Erections when waking up are common, most likely due to a full bladder. They sometimes already occur in infant boys, and in utero. Recently some scientists have begun to doubt this very much (sources: see below). The question why most men have erections when waking up ("morning wood") is still not settled.

Inhaltsverzeichnis

1 Mechanism
2 Dysfunction
3 Culture
- 3.1 Slang
4 Bibliography
5 See also

Mechanism

Image:Penis reduced.jpg Image:UncirPenisFlaccid1.jpg

Physiologically, an erection is achieved by two mechanisms that play together: increased inflow of bloodinto the vesselsof erectile tissue, and decreased outflow. The vessel system involved is known as the corpora cavernosaand the corpus spongiosum. Musclesin the region relax, allowing more blood to enter these sponge-like tissues. Contraction of other muscles reduce the outflow. The enlarged structure then exerts pressures on the exit veins, further reducing the outflow.

As blood flows in, the penis stiffens, its girth and length increases, and it rises to an angle that can vary from below horizontal to almost vertical.

Certain conditions (e.g. diabetes mellitus) result in erectile dysfunction, a problem where penile erection is insufficient to achieve normal sexual intercourse. In recent years, several drugs have been developed for treatment of this condition.

If present, the foreskinnormally retracts and exposes the glans. The skin of the scrotum tightens, pulling the testicles in towards the base of the penis.

Erection is caused by signals from the parasympathetic nervous system; it is countered by the sympathetic nervous systemwhich is mainly responsible for the "fight-or-flight" response. This explains why under stressful conditions, an erection is often difficult or impossible to achieve, and sudden onset of stress can deprive one of erection. The sympathetic nervous system is also responsible for causing ejaculation, which explains why most males lose their erection after ejaculation.

The frequency of natural erections greatly decreases from masturbating on a regular basis. This occurs because the forcing of an erection through masturbation fights off the brain's urge to get one naturally.

Erections may occur even after death, if the pressure within the penis increases for some reason, for example due to sinking fluids or the formation of gases of putrefaction. See death erection.

The clitorisof femalesalso contains erectile tissueand may become erect during sexual arousal; the erection of nipples, however, is not due to erectile tissue.

Dysfunction

Failure of the erection mechanism is known as erectile dysfunction, or ED for short. ED in humans is treated with prostheticdevices, and with prescription drugs. Some prescription drugs are injected directly into the corpus cavernosum or used as urethral suppositories, directly causing erection even in the absence of sexual excitation, while others, such as Viagra, Cialis, or Levitraare taken orally and support erection that is due to sexual excitation.

Occasionally, the foreskinof the erect penis may be very tight and immobile on the shaft, thus interfering with normal erection. This condition is known as phimosis, however it is usually very easily treatable.

Culture

In several countries, movies and magazines available to juveniles may not depict erections; such depictions are often taken as one criterion to distinguish between soft and hard pornography.

Slang

As with nearly any aspect of the human body that is involved in sex, there are many slang words for an erection. Some of these are noted in the bathroom humorarticle.

For slangterms for the "erection", see WikiSaurus:erection— the WikiSauruslist of synonyms and slang words for breasts in many languages.

Some terms would be: boner, blood sport, wang, johnson, peter

Bibliography

Harris, Robie H. (et al.), It's Perfectly Normal: Changing Bodies, Growing Up, Sex And Sexual Health. Boston, 1994. (ISBN 1564021998)

Milsten, Richard (et al.), The Sexual Male. Problems And Solutions. London, 2000. (ISBN 0393321274)

Tanagho, Emil A. (et al.), Smith's General Urology. London, 2000. (ISBN 0838586074)

Williams, Warwick, It's Up To You: Overcoming Erection Problems. London, 1989. (ISBN 072251915X)