What is Erection? How Does An Erection Happen?
When a man reaches a critical level of excitement, nerves in the pelvis signal arteries to move blood into the penis. Nerves communicate with each other through the release of nitric oxide and chemical messengers.
When the sponge-like tissue in the penis fills with blood, it results in the hardening and enlargement of the penis, causing an erection. Erections go away when the semen is released through the urethra during intercourse or masturbation.
How Does an Erection Occur
In simple words, an erection is the result of increased blood flow to the penis. Your blood vessels, hormones, muscles, and nerves all contribute to cause an erection.
It all begins in the brain as a result of physical or mental stimulation. When the brain senses a sexual urge, it sends nerves signals to the penis, telling blood vessels in the male genital organ to relax, ensuring smooth flow of
blood in the organ. When the blood travels to the penis, veins shut off to keep blood within the penis and high pressure traps it within the corpora cavernosa, causing expansion and erection of penis. An erect and firm penis is like a blown-up balloon.
When the flow of blood into the penis is stopped, the erection is reversed. As a result, the outflow channels open to allow blood to flow back so that the penis becomes soft. After orgasm, the penile veins open up to allow outflow of blood into the body. Once this happens, the blood drains out of the penis and it returns to its normal, flaccid state.
Common erection triggers include sexual urge caused by touch, sight, smell, or sexual thoughts or images, erotic
memories, and fantasies, all of which spark intense activity in the hypothalamus, causing sexual arousal signals to travel from the brain to the spinal cord to the pelvis. This causes relaxation of the muscle fibers in the corpora cavernosa and blood fills the spaces within, resulting in an eightfold increase in blood in the penis.
As a result of the increased blood flow, there is expansion of the sinusoidal spaces in the corpora, which stretches the surrounding tunica. The veins carrying blood away from the corpora are blocked off, thus trapping blood within the penis. This
raises the blood pressure and thus causes the penis to become hard and erect.
In simple words, it is the regulation of blood flow to and from the penis that causes erections.
The length of interval between erections depends on different factors, including age, physical and mental health. A young, healthy, and sexually active man may get an erection merely a few minutes after the previous erection. On the other hand, an older man in his 50s may not be able to achieve an erection before 24 hours of the first. One reason for this could be the slowed down nerve function with age.