1. Unit III The Digestive System and The Excretory System
Chapter Digestive System
Chapter 26-Excretory System

2. Digestive System-Background
Functions, Alimentary Canal, and layers

3. Functions

4. What is being digested? Lipids/fats Carbohydrates protein
Nucleic acids

5. What is Digestion?
Mechanical digestion- physical breakdown of food- making food smaller
Ex. Chewing and churning of stomach

6. What is Digestion?
Chemical digestion- using chemicals to break down food
Ex. Enzymes

7. What is Digestion?
Absorption- passing nutrients into blood from digestive system

8. What is the Digestive System?
AKA-alimentary canal or gastrointestinal tract (GI tract)
9 meter tube
Include primary organs- mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus
Include accessory organs- liver, gall bladder, pancreas, salivary glands, secrete substances which help

9. What are the 4 layers of the wall of the digestive system?
1. Mucosa-
2. Submucosa-
3. Muscular-
4. Serosa-

10. 1. Mucosa- inner most, secretes mucous, protects tissue below it, helps with secretion and absorption

11. 2. Submucosa- contains gland, blood, lymph vessels and nerves
Nourishes tissue and carries away absorbed materials

12. 3. Muscular- contains involuntary smooth muscle
Rhythmically mix food with secretions via peristalsis- muscles propel food movement forward

13. 4. Serosa- outermost visceral peritoneum- protects underlying tissues and secretes fluid to lubricate outer surface