The urethra is a tube that connects the bladder to the urinary opening for the removal of urine from the body of both females and males. It is the vessel through which urine passes after leaving the bladder, and the conduit in men for semen during sexual intercourse.
Females use their urethra only for urinating, but males use their urethra for both urination and ejaculation. The urethral sphincters are two muscles used to control the exit of urine in the urinary bladder through the urethra, and allow for voluntary control over urination (e.g., muscles that allow a person to “hold” or release their urine, or pee).
In the human male, the urethra is around 7-8 inches long and opens at the end of the penis. This is the hole at the tip of the penis that both urine and semen are released from.
The urethra is divided into four parts in men, named after the location where they are found:
- Pre-prostatic urethra – the portion of the urethra which passes almost vertically through the wall of the urinary bladder, before it enters the prostate gland
- Prostatic urethra – the portion of the urethra that traverses the prostate
- Membranous urethra – the intermediate part of the urethra that connects the prostatic urethra to the penile urethra
- Spongy urethra (or penile urethra) – the portion of the urethra that traverses the penis
It is important to note that the urethra is different from the ureter, which are muscular tubes that move urine from the kidneys to the urinary bladder. Though they sound similar, they are different.