1. The Excretory System

2. Excretion
= The process by which wastes and excess substances are removed from an organism
Organs of excretion are:
Lungs
Kidneys
Liver
Skin

3. Liver
Liver – removes harmful substances from the blood such as bacteria, certain drugs, and hormones
The liver breaks down excess amino acids to form urea
Too much alcohol can lead to cirrhosis of the liver
Bile is considered an excretory product of the liver

4. A healthy liver and the liver of a person with cirrhosis

6. Kidneys – filter urea from the blood to make urine
The Urinary System
The urinary system is included in the excretory system.
Kidneys – filter urea from the blood to make urine
Ureter – tube through which urine passes from each kidney to the urinary bladder
Urinary Bladder – where urine is stored
Urethra – the tube that carries urine from the bladder to the outside of the body

7. Kidneys Organs of the excretory system that act like filters.
The two kidneys are located near the spine in the middle of the back.
They are protected by lower ribs and covered by layers of fat.
Without the kidneys, it would not take long before the body’s system would be poisoned.
It is possible to function with only one kidney.

8. Urine Waste drains out of the kidneys in the form of urine.
Urine is about 95% water and 5% urea (protein from protein breakdown).
Fresh urine has no bacteria in it.

9. Lungs
An organ of the excretory system that rids the body of carbon dioxide and water (water vapor).

10. Skin An organ in the excretory system which removes excess heat.
When the body becomes too warm, extra heat is lost
Evaporation of sweat removes heat and cools the body

11. The skin is the largest organ in the body
It contains sweat glands through which sweat is released
Sweat is made up of:
98% water
2% salt
Small amounts of urea

12. Excretory Disorders
Kidney stones - result when urine becomes too concentrated and substances in the urine crystallize to form stones
Risk factors:
-Family or personal history
-Being an adult (40+)
-Being a man
-Dehydration
-Diets high in protein, sodium, and sugar
-Obesity
-Digestive diseases and surgery
-Other medical conditions

13. Excretory Disorders
Renal Failure – results when the kidneys fail to function correctly which leads to abnormal levels of fluids in the body
Kidney dialysis averages 4 hours per session, 3 times per week.

14. Ways to Protect Your Kidneys
Eat a diet low in fat and salt
Exercise most days of the week
Drink water (~8 glasses/day)
Avoid tobacco
Limit alcohol