Erection Process

Erection Process

It’s the flow of blood into two tube like structures that run the length of the penis that make erection occur. Various stimuli make the brain order blood to flow into these tubes and engorge them. After ejaculation, the blood recedes back resulting in the penis losing its erection. However the time it takes to lose erection depends on the length and thickness of the penis

Typically, erection occurs from sexual stimuli. It can also result from a full urinary bladder. Sometimes erection occurs spontaneously in sleep. It has been discovered that most spontaneous erections happen during REM sleep.
When a mechanical stimulus is applied (for example, during masturbation), the central nervous system of the body is not involved as erection is initiated by what’s called autonomic nervous system. Autonomic nervous system is the one that controls all the body activities that occur without conscious effort by us. For example beating of the heart, digestion process, respiration, salivation etc. are controlled by the autonomic nervous system. The part of the autonomic nervous system that’s responsible for erection is called parasympathetic.

When stimulus occurs, parasympathetic initiates releases nitric acid into the arteries resulting in the arteries dilating. That result in the tubes through the penile shaft getting flooded with blood and erection occurs.
In the absence of mechanical stimulus, it’s the cerebral cortex that initiates erection in response to smell, visual stimulus or even imagination. The cerebral cortex acts through points in the lumbar and spinal cord to initiate erection.
Once erection occurs, the penis can take different shapes depending upon the shape of the tube. The normal is straight at a 45-90 degree angle. However, it could also be bent and sometimes it’s very tightly curved resulting in what’s called Peyronie's disease. It causes psychological and physical effects on the person and needs to be treated professionally.