2. Blood sugar levels regulated by pancreatic hormones insulin and glucagon

3. Obtaining essential nutrients Storing protein for growth

4. Can be obtained by eating a diet of corn and beans Body cannot make these

5. Vitamins: non-energy foods, organic molecules required in small amounts, regulate body functions

7. Minerals: non-energy foods, inorganic molecules required in small amounts, regulate body functions

8. FOOD TYPES & FEEDING MECHANISMS Suspension feeders Substrate feeders Fluid feeders Bulk feeders

9. Intracellular Digestion Sponges Heterotrophic protists FOOD PROCESSING Ingestion Digestion Absorption Enzymatic hydrolysis

10. Extracellular Digestion Occurs within compartments that are continuous with the outside of the animal’s body Specialized cells secrete enzymes Gastrovascular cavity with single opening – Cnidarians Platyhelminthes? Alimentary canal - Nematodes, Annelids, Mollusks, Arthropods, Echinoderms, Chordates

11. Complete Digestive System: mouth, pharynx, crop, gizzard, intestine, anus

12. PHYSICAL DIGESTION Mastication – chewing Deglutition – swallowing Peristalsis – wave like muscle contractions through alimentary canal Segmentation – mixing food & enzymes Emulsification – bile from liver breaking large lipids into small lipids

13. CHEMICAL DIGESTION Carried out by hydrolases Proteins → amino acids Carbohydrates → disaccharides Disaccharides → monosaccharides Lipids → glycerol + 3 fatty acids Nucleic acids → nucleotides

14. Alimentary canal? Accessory organs?

15. Oral cavity: begins physical digestion (chewing) and chemical digestion of carbohydrates (salivary amylase) Note epiglottis & peristalsis

16. STOMACH Begins breakdown of proteins Gastrin Pepsinogen → pepsin HCl Mucus Chyme Pyloric sphincter Cardiac sphincter NOTE

17. Makes bile Stores bile Secretes sodium bicarbonate and enzymes Accessory organs: liver, gall bladder, pancreas Hormones: Secretin Cholecystokinin

18. Enzymatic Digestion - Human

19. Activation of protein digesting enzymes in small intestine Break down large polypeptides into shorter chains Enteropeptidase – triggers activation of enzymes

20. ABSORPTION OF NUTRIENTS Capillaries: monosacch., aa., minerals, vitamins, water, some glycerol Lacteals: fatty acids & most glycerol *

21. INTESTINES Small Intestine: Length (6 m); surface area (300 m 2 ) Duodenum (digestion) Jejunum & Ileum (absorption) Hepatic portal system Large Intestine (colon): Ascending, Transverse, Descending, Sigmoid Cecum, Appendix, Rectum, Feces Absorption of water Bacteria

22. Dentition & Diet Canines – killing & ripping Incisors – biting Molars - grinding

23. Longer intestine for processing fibrous diet Cecum – fermentation chamber housing symbiotic bacteria

24. Ruminant digestion – most elaborate adaptation of all herbivores; aided by symbiotic bacteria and protists