Discover

:''This article discusses human physiological erection. For erection of artificial structures, see construction.''
:''"Ithyphallic" redirects here. You may be looking for the Nile album.''
The 'erection' of the penis, clitoris or a nipple is its enlarged and firm state. It depends on a complex interaction of psychological, neural, vascular and endocrine factors. The term is also applied to the process that leads to this state.
In many countries, movies and magazines available to juveniles may not depict penile erection; such depictions are often taken as one criterion to distinguish between soft and hard pornography.

Contents

Slang

Penis erection

Shape and Size

Public Display Issues

Clitoral erection

Nipple erection

Bibliography

See also

Slang

As with nearly any aspect of the human body that is involved in sexual intercourse, there are many slang words for an erection; see — the WikiSaurus list of synonyms and slang words for erection in many languages.

Penis erection

A penis erection occurs when two tubular structures that run the length of the penis, the corpora cavernosa, become engorged with venous blood. This may result from any of various physiological stimuli. The ''corpus spongiosum'' is a single tubular structure located just below the ''corpora cavernosa'', which contains the urethra, through which urine and semen pass during urination and ejaculation, respectively. This may also become slightly engorged with blood, but less so than the corpora cavernosa. After a man has ejaculated during sexual encounter or masturbation, his erection usually ends, but this may take time depending on the length and thickness of the penis.
Penis erection usually results from sexual stimulation and/or sexual arousal, but can also occur by such causes as a full urinary bladder or spontaneously during the course of a day or at night, often during erotic or wet dreams (see "nocturnal penile tumescence"). An erection results in swelling and enlargement of the penis. Erection enables sexual intercourse and other sexual activities (sexual functions), though it is not essential for all sexual activities.

In the presence of mechanical stimulation, erection is initiated by the parasympathetic division of the autonomic nervous system (ANS) with minimal input from the central nervous system. Parasympathetic branches extend from the sacral plexus into the arteries supplying the erectile tissue; upon stimulation, these nerve branches initiate the release of nitric oxide, a vasodilating agent, in the target arteries. The arteries dilate, filling the ''corpora spongiosum'' and ''cavernosa'' with blood. Erection subsides when parasympathetic stimulation is discontinued; baseline stimulation from the sympathetic division of the ANS causes constriction of the penile arteries, forcing blood out of the erectile tissue.
The cerebral cortex can initiate erection in the absence of direct mechanical stimulation (in response to visual, auditory, olfactory, imagined, or tactile stimuli) acting through erectile centers in the lumbar and sacral regions of the spinal cord. The cortex can suppress erection even in the presence of mechanical stimulation, as can other psychological, emotional, and environmental factors.
The opposite term is .

Shape and Size

An erect penis can take on a number of different shapes and angles, ranging from a straight tube angled at a 45-90 degree angle, to a curvature to the left or right, up or down. A tightly curved penis, known as Peyronie's disease, is identified by a severe curve in the erect penis. This may cause physical and psychological effects for the affected individual, which could include erectile dysfunction or pain during erection. Treatments include oral medication (such as Vitamin E) or surgery, which is most often reserved as a last resort.
Generally the size of an erect penis is fixed throughout life and little can be done to increase the size without modifying these tissues directly through surgery on the penis.

Public Display Issues

While experiencing an erection causes no harm to anyone, the public display of an erection is severely stigmatized and frowned upon in most modern societies. Generally children entering into puberty are the most prone to experiencing uncontrolled erections, but it can occur at any time in life.
Direct physical prevention is possible by wearing tight-fitting elasticized underwear, compression shorts, or athletic supporter and tucking the flaccid penis in a downward position in the pouch. If an erection does occur, the tight-fitting elastic fabric will overcome internal blood pressure to constrict enlargement and prevent the suppressed erection from being visible, without causing harm to the restricted penis.

Clitoral erection

Clitoral erection is a part of sexual arousal in women. The clitoris is the anatomically homologous counterpart of the penis, and the physiological mechanism of its erection is similar.
Swelling and enlargement also occur during a clitoral erection but because a large proportion of the clitoris is within the body, it may not be obvious.

Nipple erection

Nipple erection may result from three kinds of response. It happens in females during breast feeding. It is also an early part of the sexual response in females and males. Both of these are caused by the release of oxytocin. Nipple erection can also be caused by cold temperature in both male and female. This is merely due to tactile response to cold temperature rather than anything linked to sexual drive. The erection of nipples is not due to erectile tissue, but due to the contraction of smooth muscle under the control of the autonomic nervous system.

Bibliography

★ Drake, Richard, Wayne Vogl and Adam Mitchell, ''Grey's Anatomy for Students''. Philadelphia, 2004. (ISBN 0-443-06612-4)

★ Harris, Robie H. (et al.), ''It's Perfectly Normal: Changing Bodies, Growing Up, Sex And Sexual Health''. Boston, 1994. (ISBN 1-56402-199-8)

★ Milsten, Richard (et al.), ''The Sexual Male. Problems And Solutions''. London, 2000. (ISBN 0-393-32127-4)

★ Tanagho, Emil A. (et al.), ''Smith's General Urology''. London, 2000. (ISBN 0-8385-8607-4)

★ Williams, Warwick, ''It's Up To You: Overcoming Erection Problems''. London, 1989. (ISBN 0-7225-1915-X)

See also

★ Priapism

★ Sexual function

★ Death erection