Anatomy of the Penis
The penis is made up of three separate cylinders. The two paired cylinders called the Corpora Cavernosa are the force behind a man's erection and are made up of chambers that expand and fill with blood to the point of turgidity, creating the hardness of the erection. The corpora cavernosa are surrounded by a membrane, called the tunica albuginea which also contributes to erections by helping to hold blood in the penis.
The capacity of the Corpora Cavernosa to fill with blood during arousal limits erection length and thickness, and this function can decrease with age.
The third cylinder of the penis, located in a groove underneath and between the two larger cylinders, is called the Corpus Spongiosum, through which semen and urine are passed out of the body. Also housed within it are nerves, two main arteries and several veins. The Corpus Spongiosum also forms the head (or glans) of the penis.
Recently, it has been discovered that the penile tissue of the Corpora Cavernosa responds strongly to various herbal compounds. Because this tissue is highly vascular (contains a high density of veins and arteries) these ancient cures for vascular and circulatory health are seeing a re-emergence in Western medicine as treatments for erection problems.
The chambers of the corpora can adapt to greater capacity and more effective function, so long as they receive the right supplementation and stimulation.
Physiology Of An Erection
An erection is the result of a combination of both physical and psychological stimulation. They are started with nervous responses between the brain and the muscles Various neurotransmitters in the brain (including acetylcholine, epinephrine, and nitric oxide) create nerve impulses that then trigger the muscles in the penis that control blood flow into the corpous cavernosa. These muscles relax, allowing large amounts of blood to flow into the penis. The spaces in the corpous cavernosa then fill with blood.
Arousal (both physical and mental) also causes nerve activity that tells the vascular system to increase blood flow to the penis. The two main arteries in the penis pump in more blood, creating pressure that inflates it to form an erection.
As the penis needs to retain the blood to remain erect, each body of erectile tissue is surrounded by an elastic membrane – the tunicae – which hold the blood from leaving the penis. This is what allows the penis to become inflated.
After stimulation is over, or following ejaculation, these reactions reversed. The pressure in the penis is reduced as the tunicae loosen and the smooth muscle in the blood vessels contract. This stops the inflow of blood, and opens the veins for the blood to flow back out. The penis then contracts back to its flaccid size.