An additional part of the penis we have thus far ignored is the corpus spongiosum, located in the groove beneath the two cylinders of the corpora cavernosa. Like them, this chamber is composed of spongy tissue that fills with blood during an erection, though to a lesser extent than the corpora cavernosa. More important, the corpus spongiosum contains the urethra, the tube through which urine and semen travel. Though cylindrical for most of its length, the corpus spongiosum differentiates at its end to form the glans, or head, of the penis, one of the areas of the body densest in nerve endings and thus one of the most sensitive, making it a central player in creating that original signal to produce an erection.

More about that signal now. The neurophysiological mechanisms involved in the process of arousal can appear so complicated that it sometimes seems like a miracle that anyone ever gets an erection. Cenforce Soft 100mg The simplified version goes like this:

The autonomic (in other words, not consciously controlled) functions of the body, such as pulse rate and, yes, erections, are controlled by two parts of the nervous system called sympathetic and parasympathetic. The sympathetic system is responsible for charging the body for “fight or flight” action, such as making the heart beat faster and increasing oxygen intake. The parasympathetic system is then responsible for relaxing the body after the event has passed.

And this is where the paradox lies. Remember how we learned that, for an erection to occur, the smooth muscle in the penis, which is normally contracted, must relax in order to let blood in? Buy Cenforce 50mg This means that, while your heart may race and your breath quicken at the prospect of a sexual encounter (all triggered by the sympathetic nervous system), it is actually the parasympathetic nervous system that must respond to tell your penis to relax and let the blood in. Buy Cenforce 200mg No wonder we sometimes get our signals crossed! And no wonder that the best sexual experiences usually occur in relaxed, comfortable situations.

The brain and spinal cord work in concert to produce an erection. The brain acts on erotic thoughts, visual stimulus, or mental images (psychogenic erections), while the spinal cord responds to direct touch (reflexogenic erections). This reflex action is assisted by the male hormone testosterone, and by brain messengers called neurotransmitters. In recent years, advances in molecular biology have resulted in signifiant improvements in our understanding of the cellular mediators responsible for the smooth muscle relaxation necessary for erections to take place.

Under normal, nonaroused conditions, a man’s sympathetic nervous system sends the neurotransmitter noradrenaline to his penis, which causes the smooth muscle tissue to remain contracted. When a man becomes aroused, the sympathetic nerves are inhibited and the parasympathetic nerves activate, sending the neurotransmitter nitric oxide (NO) to the penis. It is cGMP that initiates the muscular and vascular changes that lead to an erection.