Excretory System

Excretory System

1. What?

   • Lungs- CO2
   • Kidney- Urea
   • Skin- urea
   • Liver- bile salts

2. Why?

   • To expel wastes that have been made by cells as a by-product of metabolism. If waste accumulates then it becomes toxic

3. How?

   • Nitrogenous waste, water and other substances combine to make urine
   • The greater the toxicity of the waste, the more water required to dilute it for excretion

4. Where

   • Lungs- removes CO2 from blood
   • Kidney- removes urea from blood
   • Skin- removes quantities of urea from blood
   • Liver- removes pigment (haemoglobin) from warn out red blood cells

5. http://www.youtube.com/watch?v=TZMJeZL-BVg