Penile erection is a complex interaction of both halves of your autonomic (automatic) nervous system, your blood circulation, and your emotions. Therefore, the patient may have symptoms suggestive of a psychological problem, such as depression , and/or a medical problem, such as diabetes . Any one of these conditions can lead to erectile dysfunction.

Symptoms include:

  • A less firm penis
  • Fewer erections
  • Fewer spontaneous nighttime erections

Your penis is made up of cylinders with tough linings. These linings can hold large amounts of blood at sufficient pressure to keep it stiff for a period of time. Normally, when stimulated either locally or from your emotions, blood vessels that empty your penis constrict. This prevents blood from exiting. Blood vessels inside your penis open to accept more blood.