1. Chapter 30 – Digestive and Excretory Systems

2. Foods – these are necessary
Carbohydrates
Fats
Proteins
Vitamins
Minerals
water

3. Human Digestive System

4. Digestion starts in the mouth
Saliva starts mixing food
with saliva
- saliva comes from salivary
glands in the cheeks and
under the tongue.
- saliva moistens food,
mixes food with mucus, and
adds enzymes that break down
starch into sugars.

5. Teeth carry out mechanical digestion
Take care of your teeth

6. Swallowed food passes into the esophagus then the stomach
Peristalsis is responsible for pushing food in one direction through the rest of the digestive system after the mouth.
This occurs in the espophagus, stomach, small intestine, large intestine, rectum, and pushes wastes out of the anus.

12. Digestive system problems:
Food poisoning
Parasites such as worms
Viral infections (hepatitis)
Eating disorders (anorexia and bulimia)
Diarrhea and constipation
Flatulence! (excuse me!)

13. Excretory System
Animals produce waste products that must be removed from their body.
Most animals have a system that deals with nitrogen-rich wastes from the breakdown of proteins and nucleic acids.
Ammonia (NH3) is toxic.
In addition, it helps maintain homeostasis – balancing osmotic action and pH.

14. Human Excretory System

17. Excretory System Problems
Kidney stones – crystalized mineral salts and uric acid salts in the urine. Stones block flow of urine and cause excrutiating pain.
Kidney failure - can be caused by long-term diabetes, infections, physical injuries, chemical poisoning. Causes toxic materials to build up to lethal levels.
Dialysis or kidney transplant is the treatment.

18. The End