1. THE EXCRETORY SYSTEM
Section 3.3

2. Excretion Excretion = the process of removing waste
CO2 = respiratory system
Solid waste= digestive system
 this is not a waste product, but instead left over undigested food materials such as fiber
Wastes dissolved in water = excretory system
Excretion

3. How the Excretory System works…
1a) Cells waste diffuses into blood stream
1b) Liver waste dissolves in blood stream
Proteins are broken down by the liver for energy and Ammonia
Liver also changes ammonia to a less toxic substance called urea (liver waste)
2) All blood then passes through kidneys
(1 L/min)
2b) Tiny tubes in kidneys, called nephrons, collect waste from blood vessels (filters)
2c) Ureter carries waste to bladder = urine
Urine exits body through the urethra
Without a method of getting rid of waste, cells would soon poison themselves and die

4. KIDNEYS
In addition to filtering your blood, kidneys also maintain the balance of water in your body to keep blood pressure in check

5. Excretory Video