Your Urinary System

How Your Urinary System Works
Your urinary organs work in concert to keep your body chemicals and water in balance as they remove waste. The urinary system removes a type of waste called urea from your blood.

Here's How it Works:
  • Urea is produced and carried in the bloodstream to your kidneys — when foods containing protein break down in the body.
  • It is the kidney's job to filter the blood and remove the urea — among other duties. Urea, water and other waste substances makes up your urine.
  • Urine travels from the kidneys down two thin tubes called "ureters" to the bladder. Muscles in the ureter walls constantly tighten and relax to force urine downward and away from the kidneys. Small amounts of urine are emptied into the bladder about every 10 to 15 seconds. If there' is a back up in the flow of urine, it can lead to a kidney infection. 
  • The bladder acts as a urine storehouse and empties when you go to the bathroom. A hollow muscular organ shaped like a balloon, your bladder can normally hold up to 2 cups of urine comfortably for 2 to 5 hours.
  • Circular muscles called sphincters help keep urine from leaking. The sphincter muscles close tightly like a rubber band around the opening of the bladder into the urethra, the tube that allows urine to pass outside the body.
  • Nerves in the bladdertell you when it is time to empty. You get a feeling that you need to urinate as your bladder fills. The more the bladder fills, the more you need to go to the bathroom. The nerves in your bladder keep sending more and more urgent signals to your brain, triggering your search for a bathroom!
  • During urination, the brain signals the bladder muscles to tighten, squeezing urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax. As these muscles relax, urine exits the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.

Urine Elimination

You normally eliminate about a quart and a half of urine each day but this amount depends on many factors:
  • The amounts of fluid you drink.
  • The amount of food you eat.
  • How much fluid is lost through sweat. 
  • How much fluid you lose through breathing.
  • Medications you may be taking.



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