How does erection occur?
In order to get an erection, several parts of the body must work together. The brain sends a message of sexual arousal through the nervous system to the penis. This message causes the muscles along the penis to relax. At the same time, the artery to the penis dilates to twice its diameter, increasing the blood flow sixteen-fold, and the veins which carry blood away from the penis are blocked.
As a result, the two spongy-tissue chambers in the shaft of the penis fill with blood and the penis becomes firm. A breakdown in any of these systems makes getting or keeping an erection difficult.
The penis contains two chambers, called the corpora cavernosa, which run the length of the organ. A spongy tissue fills the chambers. The corpora cavernosa are surrounded by a membrane, called the tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues, spaces, veins, and arteries. The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa.
Erection begins with sensory and mental stimulation. Impulses from the brain and local nerves cause the muscles of the corpora cavernosa to relax, allowing blood to flow in and fill the open spaces. The blood creates pressure in the corpora cavernosa, making the penis expand. The tunica albuginea helps to trap the blood in the corpora cavernosa, thereby sustaining erection. Erection is reversed when muscles in the penis contract, stopping the inflow of blood and opening outflow channels.
Erection, in the sexual sense, is the hardening, enlarging and rising of the penis which often occurs in the sexually aroused male. Erection enables sexual intercourse and some other sexual activities, though it is not essential for all of them. In addition to sexual arousal, erection can be caused by friction, retraction of the foreskin, or by the pressure of the filled urinary bladder. In healthy males, erections occur several times per night during the REM phases of sleep, and morning erections when waking up are common. These are called an "unprovoked erection". It is normal for them to occur 2 to 3 times a week. This is a good sign the erection pathways are functioning well. Erections already occur in infant boys, and in utero.
Physiologically, an erection is achieved by two mechanisms that play together: increased inflow of blood into the vessels of erectile tissue, and decreased outflow. The vessel system involved is known as the corpora cavernosa and the corpus spongiosum. After a signal from the sympathetic nervous system, muscles in the region relax, allowing more blood to enter the sponge-like tissues. Contraction of other muscles reduce the outflow. The enlarged structure then exerts pressures on the exit vein, further reducing the outflow.
More information on impotence (erectile dysfunction)
What is impotence or erectile dysfunction? - Impotence is the inability of the male to have an erection. Some men may become impotent after having diabetes for a long time because the nerves or blood vessels have become damaged. Impotence may have a physiological or psychological basis.
How does erection occur? - Erection begins with sensory and mental stimulation. Impulses from the brain and local nerves cause the muscles of the corpora cavernosa to relax, allowing blood to flow in and fill the open spaces.
What causes impotence? - A common cause of impotence is a high level of atherosclerosis in the arteries feeding the penis. Damage to arteries, smooth muscles, and fibrous tissues, often as a result of disease, is the most common cause of impotence.
What are the physical causes of impotence? - Physical impotence occurs when there is a problem with any of the systems needed to get or maintain an erection. Hardening of the arteries can affect the artery leading to the penis so that it cannot dilate enough to deliver all the blood necessary for an erection.
What are the psychological causes of impotence? - Psychological causes of impotence often include work pressures, financial worries, fear of aging, or frustration with relationships. Depression and anxiety disorders are cited as the most common causes of psychological impotence.
How is impotence (erectile dysfunction) treated? - Treatment depends on the cause. Testosterone supplements may be used for cases with hormonal deficiency. Drugs for treating impotence can be taken orally or injected directly into the penis.
What're non-prescription treatments for impotence? - Among the herbs used for erectile dysfunction are yohimbine, gingko biloba (to increase blood flow), ginseng, pygeum, and muira puama. A penile sheath is a rigid or semi-rigid support put over the penis to support it for intercourse.
What is MUSE? - MUSE is short for "medicated urethral system for erection." This treatment is based on the discovery that the urethra can absorb certain medications, which can then pass into the surrounding erectile tissue creating an erection.
What is Viagra (sildenafil citrate)? - Viagra (sildenafil citrate), a prescription medication for the treatment of erectile dysfunction, is the first pill available that's been proven to improve erections in most men with impotence.
What is Levitra (vardenafil)? - Levitra (vardenafil HCl) is a PDE inhibitor drug. This medication helps improve erection during sexual arousal and activity but erection should end after sexual activity is complete.
What is Cialis (tadalafil)? - Tadalafil (Cialis?) is a drug used to treat male erectile dysfunction (impotence). The generic name for this compound is tadalafil.
What about penile injection therapy? - Penile injection therapy is non surgical technique used to treat impotence. Penile injections have the advantage of not involving surgery. They are also effective in many dialysis patients.
What are penile implants for impotence? - Penile implants (often called "internal penile pumps") are one of several erectile dysfunction treatment options. The inflatable penile prosthesis is a pump system surgically placed in the penis.
What is hormonal therapy for impotence? - Sexual desire (libido) and an overall sense of well-being are likely to improve when serum testosterone levels (the level of the male hormone in the blood) are restored.