2. What liquid waste do we make? Digesting protein makes poison  nitrogen waste = ammonia = poison H CO 2 + H 2 O NH 2 = ammonia H H N C—OH || O H | —C— |

3. Nitrogen waste disposal  need to save H 2 O  evolved less poisonous waste product than ammonia Ammonia  urea  excrete urea & H 2 O as urine

4. Kidneys: Structure and Function  Filter the blood to remove wastes from it, regulate salt & water balance & maintain blood pH thus maintaining the homeostasis of body fluids  Located just above waist near back on both sides- vulnerable (redundant)

5. Urinary sytem Urine pathway: Kidney->Ureter->Urinary bladder->Urethra Ureters: Tubes that carry urine from kidneys to urinary bladder Urinary bladder: smooth muscle bag that stores urine Urethra: urine passes out of the body through this tube Kidney Ureter Bladder Urethra

6. Nephron: The unit of the kidney Microscopic functional unit of kidney (approx. 1million per kidney) Inverse concentration process

7. Skin: largest excretory organ The skin removes many contaminants Sweat (sudoriferous) glands flush salts, urea, & lactic acid from blood Sebaceous (oil) glands release lipids from blood