1. Digestive and Excretory Systems
Chapter 49
Digestive and Excretory Systems

2. Nutrition Label

3. Vitamins

4. Trace Elements

5. USDA Food Pyramid

6. Digesting
Food Molecules

7. Digestive System in the Human Body

8. Inside the Human Coelom

9. Cross Section of the Small Intestine

10. Human Kidney Structure

11. How a Kidney
Machine Works

12. Excretory System in
the Human Body

13. A meal may take up to three days to pass through your digestive system
A meal may take up to three days to pass through your digestive system. It spends about three hours in your stomach.

15. About 150 liters (33 gallons) of fluid pass through your kidneys every day. But 99% of this cleaned and goes back into your blood. In their lifetimes, adults pass about 40,000 liters (8,800 gallons) of urine. This is enough to fill 500 bath tubs.

16. About 96% of urine is water
About 96% of urine is water. It also contains some waste salts and a substance called urea. Urea is made during the breakdown of proteins in your liver. Urea may also leave your body in sweat. If urea builds up in your body, it is a sign that your kidneys are not working properly. Kidney failure can be fatal if it is not treated quickly.