1. Liquid Excretion: removal of liquid wastes & water/salt balance
Ch 38.3
The Urinary System

2. Nitrogen wastes are excreted & cycled
Nitrogen in
Plant & animal
protein
Ammonia nitrogen
Is excreted in urine
Bacteria convert
Ammonia to usable
Nitrate fertilizer

3. Forms of Nitrogen Wastes
Toxicity
Environment& removal
1. Ammonia
Most
Water by diffusion
2. Urea
Less
kidney as urine
3. Uric Acid
crystal
Least
Air & Deserts as
A dry crystal

4. Protein Building blocks:
H-N H
R.Gr.
C=OH H
Amino
NH2
Acid
COOH

5. Nitrogen waste from Protein Breakdown
Kidney filters the blood
Removes urea waste
Recycles food, water & salt
Urine = urea waste, water & salt

6. Bladder stores Urine made by Kidneys
Ureter tubes
Carries urine to urethra

7. Nephron: Unit of filtration

8. Water levels in urine under control of Hypothalamus & ADH hormone

9. Kidney Transplants: