The idea of how actually your penis becomes erect scarcely comes to your mind until you experience problems with achieving erection or orgasm.
Usually it takes not much effort for a man to have erection. However, the whole range of factors play their role in keeping good erection for enough time to bring satisfaction for a man and his sexual partner. In case any of these factors fails, a man can experience erectile dysfunction (ED).
Penis has three main structural “layers”, which are the corpora cavernosa, the corpus spongiosum and the tunica albuginea. The first one is responsible for extending the penis length, with the second one covering it. In the latter layer the urethra is located, the opening in the penis through which a man urinates and ejaculates. There are also lots and lots of arteries, veins and muscles that go through the penis and provide for its filling with blood and stiffening.
To achieve an erection a man needs to think of something sexually exciting or physically stimulate the penis. When an erection comes, the brain send nervous signals to the penis “telling” it to relax and thus be filled with blood.
When blood comes to the penis, it is locked there by appropriate tissues and membranes, which holds the erection. The testicles also play important role in this process, releasing the testosterone, which determine the flow of erection.
After the orgasm or if the stimulation stops, the blood does not come to the penis anymore and erection ends.
There are many reasons for which erectile dysfunction may happen, both physiological and psychological. Your mind and body should work in harmony for you to achieve healthy erection. In any case it is important to apply for the professional help and no practice self-treatment as it may bring more harm then benefit.