Erectile dysfunction (impotence) is inability to get an erection or problem keeping an erection firm enough for sex and/or a reduced sexual desire that, when on an ongoing basis, it usually affects your self-confidence and causes stress, and relationship problems, frequently creating an issue for you or your partner.
An erection is an emotional event that begins in the brain. Physical and/or mental stimulation cause nerves in the brain to send chemical messages to nerves in the penis telling the penile blood vessels to relax so that blood can flow freely into the penis. Once in the penis, high pressure traps the blood within both corpora cavernosa. This causes the penis to expand and sustain an erection. Erection is reversed when the inflow of blood is stopped and opening outflow channels open, allowing the penis to become soft