Penile erection vascular system

Erectile dysfunction can result from any single abnormality or combination of abnormalities of the four systems necessary for a normal penile erection. Vascular, neurologic, or hormonal etiologies of erectile dysfunction are collectively referred to as organic erectile dysfunction. About 80% of patients with erectile dysfunction have the organic type. Patients who fail to respond to psychogenic stimuli have psychogenic erectile dysfunction. 

ED can result from an abnormality in one of the four systems necessary for a normal penile erection or from a combination of abnormalities. Vascular, nervous, or hormonal etiologies of ED are referred to as organic ED. Abnormality of the fourth system (i.e., patient s psychological receptivity to sexual stimuli) is referred to as psychogenic ED. 

The incidence of erectile dysfunction is low in men less than 40 years of age. It increases as men age, likely as a result of concurrent medical conditions that impair the vascular, neurologic, psychogenic, and hormonal systems necessary for a normal penile erection. 

A normal penile erection requires the full functioning of several physiologic systems vascular, nervous, and hormonal. The patient must also be psychologically receptive to sexual stimuli. 

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