1. The excretory system

2. What is excretion? Excretion: The removal of wastes produced by cells.
Major Cellular Wastes:
Carbon Dioxide
Water
Mineral Salts
Nitrogenous Compounds
Compounds such as Urea and Uric Acid that are produced from the breakdown of protein.

3. Parts of the Excretory system
Lungs
Liver
Skin (Sweat Glands)
Urinary System
Why do we need excretion?
If cellular wastes accumulate in the body, you may become sick or die.

4. Excretion in the lungs
Lungs exhale carbon dioxide, which is a waste product of cellular respiration.

5. Excretion in the liver Large multipurpose organ.
Produces Urea (nitrogenous compound) from excess Amino Acids
Purifies blood by removing drugs and alcohol.

6. Excretion in the skin Sweat Glands excrete perspiration
Perspiration composed of:
Urea
Salt
Water

7. Excretion in the Kidneys
The urinary system
Excretion in the Kidneys

8. Diagram of the
Urinary System

9. Excretion by the urinary system
Kidneys: filter the blood and produce urine through subunits called nephrons.
Ureters: transport urine from the Kidneys to the Bladder.
Urinary Bladder: temporarily stores urine.
Urethra: single tube that excretes the urine from the body.

10. The kidneys
Useful substances are removed from the kidney and returned to the blood.
Glucose
Amino Acids
Some salts
99% of Water
Urine proceeds through the urinary system and is eventually excreted.
Urea
Some Water
Some Salts