1. 9.4 Digestion in the Mouth and Stomach

2. Mouth Physical digestion-chewing

3. Mouth Chemical digestion Saliva -1 litre per day -makes food wet (mucous, enzymes) -Bolus ( a wet ball of food) -Enzyme: salivary amylase starch  disaccharides

4. Swallowing Tongue Soft palate protects nasal openings Epiglottis protects airways

5. Peristalsis Waves of smooth wave-like muscle contractions

6. Structure of the Stomach 2L capacity Site of protein digestion

7. Sphincters Circular muscle Relaxed, food can move through

8. Stomach Layers: mucosa innermost layer, mucosa secretes digestive juices replaced every 3 days

9. chyme food & gastric juice in the stomach

10. Gastrin Hormone released when food is present in the stomach 2L of gastric juices released each day

11. Acid hydrochloric acid, pH 2.0-3.0 kills germs Activates enzymes (pepsinogen  pepsin) nerves in walls of stomach stimulate churning

12. Acid Reflux Improperly closed GI sphincter Medicine: tums, rolaids,