Basically, an erection occurs when blood engorges the penis, filling the spongy erectile tissue within resulting in an enlarged and stiffened unit.
For this amazing structure to build on cue, a lot has to go right. First, the brain, realising it is aroused, beams messages to the blood vessels that supply the penis with blood. This causes them to relax and widen, allowing more blood to flow in. The veins that usually carry blood away from the penis are then compressed, trapping the extra blood inside, causing the penis to remain erect until orgasm.
As far as erect penises go, there are two types. One type, 'growers' expand and lengthen when they are aroused, while others, 'showers' retain their girth most of the time and don’t grow much bigger during an erection. According to an international Men's Health survey, 79 per cent of men have growers, while 21 per cent have showers.
And did you know… sometimes men have erections involuntarily, including when they least desire one, refusing to deflate, much to their embarrassment!
Often erections occur outside of a man’s control. It is usually sexual stimulation that causes them to grow, but anything from a warm breeze, the need to urinate or an idle thought can trigger an erection.
This is why, on average, men sustain an erection for at least 90 minutes while they sleep. Deep relaxation can also inspire an erection, as can the hormones that are released during REM sleep. On average, a healthy male has three to five erections every night, many lasting 25 to 35 minutes.
Involuntary erections are more common among young boys (even infants can get them), but can happen to anyone. Such erections are dictated by the nerves in the lower spine and are as unconsciously controlled as digestion or breathing.
When a man has an erection, his penis often emits a clear fluid called pre-cum. The purpose of this mysterious liquid is to clean out the urethra and to help keep sperm alive as they move through the vagina towards the egg. Although pre-cum itself contains no sperm, it can sweep sperm from previous ejaculations with it as it travels through the urethra, giving it the ability to impregnate a woman if any gets inside her vagina.
Beware men: an erect penis is breakable – or 'fracturable', as the penis contains no bone to be snapped. Such a fracture occurs when an erect penis is bent too much in the wrong direction, causing a rupture or tear. For a visual, think of a sausage, which will crack if you bend it too much. Medical literature reports about 2,000 cases of such penis fracture each year, though most cases likely go undocumented because patients are too embarrassed to report it.
Most penis fractures occur during 'violent intercourse,' but there are also many cases where men damage their penises by falling out of bed with an erection.
What’s the cure? Six weeks of rest with a penis splint, or surgery.
Erections deflate following ejaculation in a process called detumescence. It is essentially the reverse of an erection: the penile muscles and arteries contract, the blood flow to the penis decreases, the veins open up, the trapped blood begins draining and soon the penis has returned to its idle state of slight contraction.
At this point, called the refractory period, it is usually difficult for a man to have another erection. This stage can last anywhere from a few minutes to a few days, depending on factors such as age and how frequently the man has sex.
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