2. Digestive System Chapter 14

3. In your groups…you will come up with a definition (using YOUR WORDS) and a colored picture of it happening in the body. You will be presenting this to the class. YOU MAY NOT USE BOOKS!!!! 1. Ingestion 2. Physical Digestion 3. Mechanical Digestion 4. Propulsion 5. Chemical Digestion 6. Absorption

4. Digestion (at organ and system level) Ingestion: take in food Physical digestion: food breakdown Mechanical: food breakdown; segmentation Propulsion: movement of food; peristalsis and swallowing Chemical digestion: breakdown of food molec. by enzymes Absorption: transport of food from GI tract to blood or lymph Defecation: elimination of indigestible substances; feces

5. Chemical Digestion vs metabolism Chemical digestion occurs in system, then cells use nutrients for metabolism Catabolism- breaking down of molecules= hydrolysis Anabolism- building up of molecules

6. Digestive System Mouth Pharynx Esophagus Stomach Sm Intestine Lg Intestine Anus GI Tract (Alimentary Canal) Teeth Tongue Salivary Glands Liver Gall Bladder Pancreas Accessory Organs

7. Histology of GI tract wall Layers: Mucosa, submucosa, muscularis, serosa Lumen: opening/hollow center Membrane: peritoneum (visceral & parietal)

8. Peritoneum- Membrane Visceral peritoneum Peritoneal cavity Parietal peritoneum

9. Nutrition, Chemical Digestion and Metabolism Nutritional polymers broken down into monomers (or building blocks) during digestion …then metabolized

10. carbohydrates proteins lipids Nucleic acids

11. Carbohydrates monosaccharide disaccharide polysaccharides Monosaccharide - glucose, fructose, galactose Polysaccharides- starches, cellulose, fiber, glycogen Disaccharides- lactose, maltose, sucrose Energy source: pasta, bread, cellulose, sugar

12. Lipids Fatty acids diglyceride Insulation, membranes, energy Fats, Oils, Waxes, Cholesterol

13. Lipids Saturated Fats: increase LDL (butter) Unsaturated Fats: decrease LDL (vegetable oils) Polyunsaturated Fats: Omega-3 ( nuts, fish oil, leafy greens) BAD FOR YOU (builds up in arteries & leads to heart disease)

14. Proteins Amino acids (building blocks) polypeptide dipeptide Tissue Maintenance and Growth, enzymes

15. Nucleic acids DNA RNA nucleotide sugar

16. Digestive organ anatomy and physiology Teeth Tongue Cheeks Lips Hard and Soft Palates *Tonsils *Uvula Salivary glands- saliva Oral Cavity Anatomy

17. Salivary Gland Secretion chemically digests polysaccharide starches into disaccharides Contains enzyme called salivary amylase (starch breakdown) SALIVA Mumps (disorder) – swelling, pain of salivary glands

18. Oral cavity physiology 1. Ingestion lips 2.& 3. Physical digestion Mechanical- mastication by teeth, mashing by tongue Propulsion- swallowing by tongue 4. Chemical digestion- saliva contains enzymes (amylase)

19. Pharynx anatomy and physiology 1. Physical Propulsion- swallowing, peristalsis

20. Esophagus anatomy and physiology Heartburn (disorder) 1. Physical Propulsion- peristalsis

21. Stomach anatomy cardia Peptic ulcers H. pylori vomiting

22. Microscopic stomach anatomy rugae

23. Stomach Secretion Gastric juice Contains HCl, pepsin(ogens), mucus, intrinsic factor, gastrin, rennin for milk proteins Pepsin(ogens) chemically digest protein subunits called polypeptides into dipeptides Food liquified into chyme

24. Stomach physiology 1. & 2. Physical Mechanical-churning, mixing Propulsion- peristalsis 3. Chemical-gastric juice contains pepsin(ogen) enzymes 4. Absorption of drugs, alcohol, and a little H2O and electrolytes- hepatic portal circulation to liver

25. Digestive System Lab

28. Liver anatomy Disorders: Jaundice (bilrubin), cirrhosis (scar), hepatitis (swelling & inflammation)

29. Liver anatomy

30. Liver secretion Produces bile which empties into duodenum of sm. intestine contains H 2 O, bile salts, pigments, cholesterol, electrolytes, phospholipids Bile salts emulsify fats into smaller fat droplets, but no enzymes

31. Liver physiology 1.Chemical digestion?? Bile salts (empties into duodenum) but contains no enzymes 2. Other functions: filters toxins, phagocytizes old RBC’s, transports lipids to lymphatic system, anabolism and stores excess nutrients after anabolism

32. Gall bladder anatomy and physiology Disorder: gallstones 1. Stores and releases excess bile from liver into duodenum

33. Pancreas anatomy and physiology Disorder: diabetes 1. Chemical digestion- secretes pancreatic juice into duodenum, contains enzymes, (see next slide)

34. Pancreas Secretion Pancreatic juice empties into duodenum of small intestine and neutralizes chyme Contains most enzymes of all organs: 1. pancreatic lipase - digest lipids 2. pancreatic amylase - digest carbs 3. nuclease - digest nucleic acids into nucleotides 4. trypsin, chymotrypsin, carboxypeptidase - digest proteins

35. Small Intestine anatomy Disorder: Lactose intolerance

36. Small Intestine anatomy Containing lacteals and microvilli VILLI

37. Small Intestine Secretion Intestinal juice with brush border enzymes Contains enzymes for complete digestion into nutrients: 1. Intestinal lipase - digest lipids 2. Nuclease - digest nucleic acids into nucleotides 3. Maltase, sucrase, lactase -digest carbs 4. Peptidases - digest proteins

38. Small Intestine physiology 1. & 2. Physical Mechanical- segmentation Propulsion- peristalsis, segmentation 3. Chemical- intestinal juice contains enzymes (see previous slide) 4. Absorption of electrolytes & NUTRIENTS!!!!- most absorption in entire system and only place to absorb nutrients!!!

39. Large Intestine anatomy Disorders: Flatulence, hemorrhoids, constipation, diarrhea

40. Large Intestine Secretion Mucus, but no enzymes Bacteria (E.coli) digest??? (no enzymes) remaining carbohydrates and proteins into odoriferous gases, released during flatulence Bacteria produce vitamin K and B

41. Large Intestine physiology 1 Physical Propulsion- peristalsis and defecation reflex 2. Chemical??-by bacteria, (see previous slide) 3. Absorption of H 2 O!!!! electrolytes- hepatic portal circulation to liver 4. Defecation

42. Overview of physiology (organs involved in each function) Ingestion-oral cavity Physical digestion mechanical- oral cavity, stomach, sm intestine propulsion-oral cavity, pharynx, esophagus, stomach, sm and lg intestine Chemical digestion by enzymes-salivary glands in oral cavity, stomach, liver??, gall bladder??, pancreas, sm intestine, lg intestine?? Absorption into blood- stomach, sm and lg intestine Defecation- lg intestine

43. Overview of physiology- chemical digestion Carbohydrates- salivary glands in oral cavity, pancreas, sm intestine, lg intestine?? Lipids- liver??, gall bladder??, pancreas, sm intestine Proteins- stomach, pancreas, sm intestine, lg intestine?? Nucleic acids- pancreas, sm intestine