Request Appointment

Understanding an Erection

The penis is made up of spongy tissue that holds blood. When the penis is flaccid (soft), blood flows in and out of the tissue. During sexual excitement, extra blood flows into the tissue. The extra blood makes the tissue swell. The penis then becomes erect (rigid). This makes it firm enough for intercourse.

A flaccid penis showing the scrotum and a cross section of tissue without extra blood

A normally erect penis showing a cross section of tissue filled with extra blood

When there’s a problem

Physical or psychological problems can keep the tissue in the penis from filling with extra blood or from holding the extra blood in. When this happens, the penis remains soft. Or, the penis gets hard but won’t stay hard. This is called erectile dysfunction.


Was this helpful?

Yes No

Tell us more.

Check all that apply.

Last question: How confident are you filling out medical forms by yourself?

Not at all A little Somewhat Quite a bit Extremely

Thank You!

Discrimination is Against the Law. We comply with applicable Federal civil rights laws. We do not discriminate against, exclude or treat people differently because of race, color, national origin, age, disability or sex.
 Visit Other Fairview Sites 
(c) 2017 Fairview Health Services. All rights reserved.