1. The Excretory System

2. Do Now:

3. Excretion – removes cellular waste
Excretory System
Excretion – removes cellular waste
The process that collects & removes harmful or useless substances that form in the body or are taken into the body from the blood, tissues, and cells.

4. Excretory System
Although the urinary system has a major role in excretion, other organs contribute to the excretory function.

5. Four Organs of the Excretory System
The lungs in the respiratory system excrete some waste products, such as carbon dioxide and water.
The skin is another excretory organ that rids the body of wastes through the sweat glands.
The liver It converts nitrogenous waste from the break down of proteins into urea.
The major task of excretion still belongs to the kidneys, the major organ in the urinary system. If it fails the other organs cannot take over and compensate adequately.

6. Cellular Waste Heat Water Salts CO2 Urea
W/O excretion poisonous wastes build up in blood, cells, and tissues.
Could lead to serious illness & eventually DEATH!

7. Kidneys & Urinary System
Urinary System – excretes waste and maintains homeostasis of body fluids.
Kidneys (main organ of the system)
Ureters
Bladder
Urethra

8. Kidneys & Urinary System
Two
Fist sized
Bean shaped

9. Urinary System - continued
Ureters
Narrow muscular tubes
Connect Kidney  Bladder
Bladder
Muscular sac
Stores Urine
Expand to fill
Muscle relaxes :
Urine squeezed into Urethra

10. Urinary System - endpoint
Urethra
Tube leading from Bladder  outside of body

11. Failures of Homeostasis
Bladder & Kidney Infections caused by bacteria from colon/rectum entering urethra.
Kidney Stones - crystallization of mineral salts & uric acid that block passage of urine
Kidney Disease - caused by long term diabetes, infections, & chemical poisoning
Gout – form of arthritis where excess production of uric acid leads to deposits of crystals in joints (esp. toes)