Erectile dysfunction is the inability to attain or maintain an erection of the penis that is firm enough for penetration during sexual intercourse. The condition is also called impotence. To initiate and maintain an erection, the penis must fill with blood. Nerve signals stimulate this blood fill. The nerves prompt certain blood vessels in the penis to expand so blood can fill it. Meanwhile, other blood vessels constrict, trapping blood inside.
Male Genitourinary System
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The following factors can cause erectile dysfunction:
Veins are compressed when blood fills the penis. This will help trap the blood in the penis. If these veins are not fully compressed, then blood can leave the penis. The inability to keep blood in the penis will make it difficult to reach or keep an erection. The compression of the veins may not occur, or may be weaker than it should if the blood vessels that are supposed to fill do not fill enough. Blood vessels may not fill enough because of injury or disease.
An erection cannot be attained if nerve signals do not prompt blood vessels to do their job or if blood flow to the penis is reduced. Nerve problems can also diminish feeling in the penis, resulting in dysfunction.
Many medications can cause erectile dysfunction by impairing either blood vessel or nerve function.
Medical conditions can also have the same effect. Examples include:
Psychological factors account for 10%-15% of erectile dysfunction cases. The brain initiates many of the nerve signals required for a successful erection. Problems in your relationship, feelings of guilt associated with sex, depression, anxiety, and stress can all lead to erectile dysfunction
Definition & facts for erectile dysfunction. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/definition-facts. Accessed January 29, 2021.
Erectile dysfunction. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T113875/Erectile-dysfunction . Accessed January 29, 2021.
Rew KT, Heidelbaugh JJ. Erectile dysfunction. Am Fam Physician. 2016;94(10):820-827.
What is erectile dysfunction? Urology Care Foundation website. Available at:
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Accessed January 29, 2021.
Last reviewed March 2020 by EBSCO Medical Review Board Adrienne Carmack, MD