To understand better about erectile dysfunction, it is important to understand how a normal erection occurs. Contrary to popular belief, the brain is the biggest sexual organ and aware of erections which are the result of a pulse sent by the brain to the central nervous system. The nervous system then tells the party’s muscular corpora cavernosa of the penis to relax. Once the corpus cavernosum called the tunica albuginea gets filled with blood, the muscular corpus cavernosum then expands. The enlarging the corpora cavernosa resultis in an erection.