Impotence - How an Erection Occurs

An erection is triggered by signals from the nervous system during sexual arousal, but it is very common for an erection to occur at other times as well such as due to friction or the retraction of the foreskin. An erection can be described as the enlarging, hardening and rising of the penis which then enables sexual intercourse. To cause an erection the blood flow in the penis has to alter and it is a two way mechanism. Firstly the muscles in the penis have to relax therefore causing the blood flow to increase to the spongy tissue therefore causing the penis to swell. Then in conjunction there is contraction of the lower muscles causing constriction on the exit vein which reduces the outflow. The penis should remain enlarged until after ejaculation when the nervous system causes the relaxing of the lower muscles which let the blood flow out.

The failure to sustain an erection is referred to as impotence or erectile dysfunction. Because the system of getting an erection is complicated there are many possibilities as to why the erection is not happening when desired. If any part responsible for producing an erection such as the brain, the blood vessels, nerves and smooth muscles are not functioning properly then there will be problems and the man could suffer from impotence or erectile dysfunction.