1. Animal Nutrition

2. Digestion 1.Reduce size of food material to increase surface area 2.Kill unwanted microbes 3.Break down macromolecules into subunits 4.Absorb small molecules into the bloodstream

3. Types of Digestion Mechanical digestion –Teeth, mouth Enzymatic (chemical) digestion –Mouth –Stomach –Small intestine

4. Enzymatic Synthesis and Digestion of Organic Polymers Digestion Synthesis

5. Intracellular Digestion Enzymatic digestion Inside food vacuole

6. Extracellular Digestion Allows digestion of larger organisms Enzymes are secreted into gastrovascular cavity

7. Alimentary Canals Specialization Increased surface area

8. Human Digestive System

9. Dentition Carnivore –Grab, cut, crush Herbivore –Grind Omnivore

10. Tooth Function

11. Swallowing

12. Stomach Mechanical digestion –Peristaltic contractions Enzymatic digestion –Pepsinogen Enzyme precursor Converted to active form pepsin by acid –Digests proteins Acid kills unwanted microbes Some absorption of nutrients –Water and alcohol

13. Small Intestine Neutralization of acid –Pancreas produces alkaline (basic) secretions Enzymatic (chemical) digestion –Source of enzymes Small intestine Pancreas Emulsification –Bile salts from liver –Increases surface area of fat droplets

14. Small Intestine Absorption of digested molecules –Structure of small intestine increases surface area Villi and microvilli –Intestinal walls are filled with capillaries –Nutrients pass through intestine wall into capillaries and into the blood stream

15. Duodenum Approximately the first foot of the small intestine Ducts from pancreas and gall bladder enter here –Pancreas – bicarbonate, hydrolytic enzymes –Gall Bladder – bile

16. Pancreas Gland –Bicarbonate – neutralizes stomach acids –Hydrolytic enzymes Carbohydrates – Amylase, disaccharidases Proteins - Trypsin, chymotrypsin, aminopeptidase, carboxypeptidase, dipeptidase DNA and RNA - Nuclease, neucleosidase Fats - Bile salts, lipase

17. Carbohydrates

18. Protein Structure

19. Proteases Aminopeptidase Trypsin and chymotrypsin Carboxypeptidase

20. DNA and RNA

21. Lipids

22. Homeostasis

23. Enzyme Activation Pancreas secretes enzymes in inactive form Enteropeptidase found in small intestine activates the enzymes

24. Intestinal Wall Structure

25. Enzymatic Digestion

26. Gastrointestinal Tracts

27. Cellulose Digestion No multicellular animal can directly digest cellulose Microorganisms live in specialized intestinal cavities to digest cellulose

28. Rumination “Chewing Cud” Rumen –Microorganisms digest cellulose –Some nutrients absorbed through wall of rumen –Rumination (chewing cud) Reticulum and Omasum –Absorb water –Slowly pass material from rumen to abomasum Abomasum –True stomach –Digestion of microorganisms –Digestion of proteins

29. Ruminant Digestive Tract