Male Erection Types
The mechanics of erection are highly complex. However, it's important to remember that although an erection depends upon several factors, voluntary control is not one of them.
In short...not everything happens below the belt.
Becoming erect is the result of a perfectly balanced process involving the brain, blood vessels, nerves and hormones...in particular testosterone.
When a man is sexually excited, the brain triggers a series of reactions which cause the nerves in the penis to release neurotransmitters, which in turn causes a dilation of the penile blood vessels.
This dilation allows the penis to fill with blood.
As the cavernous and spongy bodies of the penis become engorged, the veins that normally drain the penis of blood are compressed so that most of the blood entering the penis can't drain out.
It's this engorgement and lack of venous blood drainage that brings about an erection.
After ejaculation, the accumulated blood flows out of the penis, which then regains its normal size in a flaccid state. It's also interesting to know that upon ejaculation, the nervous system closes the orifice between the urethra and the bladder, preventing semen from mixing with urine and vice versa.
Not counting the sexual activity erection, there are three kinds of erections:
- Reflex erections - common among children and babies. These are involuntary and take place without sexual stimulation. Among adults, they can be brought on by rubbing clothes or simply the vibration of a moving vehicle. Because this type of erection is controlled by a nerve center at the base of the spine and requires no input from the brain, men with spinal injuries that have not affected this area may get reflex erections.
- Psychogenic erections - occur when a man has sexual thoughts.
- Nocturnal erections- are not well understood. but it is known that healthy men of all ages have three or four each night with each erection lasting for 30 minutes.