Sunday, October 30, 2011

2.68a - Excretion


excretion of Urea - Nitrogen is toxic to the body so it cannot be stored and must be excreted

original form of nitrogen in blood stream is amino acids

amino acids are usually used for growth but if there is extra (excess) they must be removed - rule of both liver and kidneys

- blood circulates to the liver and amino acids are converted into Urea
- it then re-enters the body and circulates to the kidneys.
- Kidneys then filter the Urea from the blood and the Urea is then added to water to form Urine which then travels down the Ureter
- Then collected in the bladder (form of Urine) - filtered blood then goes back to veins with toxic Urea removed


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