1. Digestive System Chapter 12

2. Alimentary Canal A muscular tube about 9 yards long which passes through the body’s ventral cavity

3. 4 Layers of the Alimentary Canal 1. Mucous Membrane 2. Submucosa: carry materials

4. 3. Muscular Layer: peristalsis 4. Serous Layer: lubrication

5. Mouth… Tongue: friction (Papillae-rough projections), taste Teeth: 20 primary 32 secondary

6. Palate: Hard=toward front Soft=tissue near back of throat that forms the cone-shaped projection called the Uvula (“hangy ball”)

7. Esophagus… Behind trachea, through diaphragm, lined with mucus Epiglottis closes over trachea to swallow

8. Stomach… Pyloric Sphincter-muscle at junction of esophagus and stomach A valve that prevents regurgitation of food

9. Stomach… Secretes mucus (protection), pepsin (enzyme), hydrochloric acid Absorbs water, alcohol, and some drugs

10. Pancreas… Connects with duodenum Secretes several enzymes for protein, carb, & DNA digestions

11. Releases bicarbonate ions to neutralize acid in the small intestine

12. Liver… Maintains blood sugar levels (converts glucose to glycogen) Breaks down proteins (urea)

13. Storage, detoxification, removes damaged blood cells

14. Produces bile—helps mix fats with digested material, increases absorption of fat- soluble vitamins

15. Small Intestine… Duodenum:”C” shaped, connects sm. to stomach Jejunum: Ileum: lined with villi (increases surface area)

16. Small Intestine… Secretes mucus and watery fluids Contain digestive enzymes to break down food

17. Absorption! Active transport/facilitated diffusion

18. Large Intestine… Cecum: beginning of lg. Colon: 4 portions: ascending, transverse, descending, sigmoid Rectum: anal canal, anus

19. No digestion Secretes mucus, absorbs water with electrolytes