Why is urea removed from the body

If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.

This triangle-shaped, hollow organ is located in the lower belly. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine. They contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to 2 cups of urine for 2 to 5 hours.

Two sphincter muscles. These circular muscles help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder. Nerves in the bladder. The nerves alert a person when it is time to urinate, or empty the bladder. This tube allows urine to pass outside the body. The brain signals the bladder muscles to tighten.

This squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. Ages of patients ranged from 18 to 60 yrs. Collection of urine from control patients. Measurements: Urea nitrogen and creatinine concentrations in blood, urine, and the hemodiafiltration effluent, measured every 24 hrs for 6 days. Effluent and urine volumes were measured. This is because it is at the end of chain of reactions which break down the amino acids that make up proteins.

These amino acids are metabolised and converted in the liver to ammonia , CO 2 , water and energy. But the ammonia is toxic to cells, and so must be excreted from the body. Aquatic creatures, such as fish, can expel the ammonia directly into the water, but land-based animals need another disposal method. So the liver converts the ammonia to a non-toxic compound, urea , which can then be safely transported in the blood to the kidneys, where it is eliminated in urine.

An adult typically excretes about 25 grams of urea per day. As urea goes stale, bacteria convert it back into ammonia, which gives the familiar pungent smell of lavatories. Any condition which impairs the elimination of urea by the kidneys can lead to uremia , a buildup of urea and other nitrogen wastes in the blood that can be fatal.

To reverse the condition, either the cause of the kidney failure must be removed, or the patient must undergo blood-dialysis to remove the wastes from the blood. Urea has quite an interesting history. It was first discovered and isolated from human urine by H.