• Question: what causes a man to have an erection?

    Asked by gurtrude88 to Daphne, Darren, Jon, Katherine on 22 Mar 2012. This question was also asked by bieberrocksduh.
    • Photo: Darren Logan

      Darren Logan answered on 22 Mar 2012:

      Physically, its due to a influx of blood into two spongy tubes inside the penis, called the corpora cavernosa. The blood stiffens the spongy tissue, causing the erection.

      The blood flows in there as a result of special nerves which release chemicals that cause an increase in blood flow in, and also by muscles which squeeze the veins of the corpora cavernosa, stopping the drainage of blood back out.