1. Digestive System Chapter 41

2. What you need to know!  The major compartments of the alimentary canal – oral cavity, pharynx, esophagus, stomach, small intestines, and large intestines – and their contributions to animal nutrition.  The major digestive glands – salivary glands, pancreas, liver, and gallbladder – and their contributions to animal nutrition.  The general scheme of chemical digestion of carbohydrates, fats, proteins, and nucleic acids.

3. Diet Essential nutrients are required for survival and include minerals and organic molecules (the animal cannot make itself) 1. 10/20 amino acids are essential amino acids 2. Essential fatty acids (linoleic acid is used in our cell membranes) 3. Vitamins like B and E are organic and required in small amounts 4. Minerals like Ca and P are inorganic nutrients required in small amounts

4. Food Processing 1. Ingestion: eating 2. Digestion: breakdown food a) Intracellular: broken down within the cell & protected by a membrane b) Extracellular: broken down outside the cells c) Gastrovascular cavity: ingestion and elimination from the same hole (protostomes) with digestion in an inner cavity 3. Absorption: cells absorb required molecules 4. Elimination: excrement

5. Mammalian Digestion

6. Path of Food 1. Mouth, Saliva (lubricate and amylase), & Chewing make a bolus  2. Pharynx (epiglottis prevents bolus from entering trachea) and esophagus (peristalsis) deliver  3. Stomach stores and digests with gastric juice (HCl & Pepsin) transforms bolus to acid chyme 

7. Path of Food 4. Small intestine where most chemical digestion occurs (pancreas and liver digestive enzymes)   Villi increase surface area of SI where capillaries absorb monomers and smaller molecules 5. Large intestine or colon absorbs water and compacts waste  6. Rectum stores and eliminates waste

8. Digestive Hormones  Gastrin - stomach increases gastric juices  Enterogastrone – small intestine slows peristalsis allowing for increased digestion  Secretin and cholecystokinin (CCK) – small intestine increases flow of digestive fluids from the pancreas & gall bladder (liver)