How The Bladder Works

Urine is a fluid that contains urea (the by-product created when your body breaks down protein), other waste products and water. Your body produces around two to three pints of urine a day. This is an estimate, of course, since it depends on how much you eat, drink, sweat and whether you are taking any medications such as water tablets.

The Urinary System

Urine drains from the kidneys to the bladder through tubes called ureters.

The bladder is a hollow muscular organ that stores urine your body produces. As this hollow muscle, it also expands to accommodate urine volume. On average, your bladder can hold roughly about 2 to 2 ½ cups of urine for up to five hours.

The bladder wall contains a muscle called the detrusor. This muscle relaxes allowing the bladder to fill. During urination, this muscle contracts to squeeze out the urine stream.

At the bottom of your bladder is a structure called the urethra. The length of the female urethra is shorter when compared to that of males. This is the reason why women are at more risk when it comes to urine infections.

The urethra is a tube that runs from the neck of the bladder to the outside of the body. The urethra contains two outlet valves. These to structures are called internal and external sphincters.

The internal sphincter is a ring of muscle that stabilizes the neck of the bladder. Your body opens and shuts your sphincters automatically without any conscious effort on your part. It is a natural reflex.

The external sphincter (also known as the distal sphincter) acts to keep urine in the bladder. It is controlled by the pudendal nerve, which is you control deciding whether to open it. When you need to use the bathroom and have to wait until you get to a restroom, you use this structure to restrain any urine from escaping until you're ready to.

The pelvic floor is a group of muscles that supports the bladder, bowels and, in women, the womb. It is connected to the pelvic bone, the pubic bone and coccyx or tailbone.

The pelvic floor helps to keep the urethra closed until you’re ready to pass fluids and contracts each time you cough or sneeze to control any accidental leakage of urine. The pelvic floor is what we use to control the act of flatulence (passing gas) and heightens sexual awareness during intercourse.