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Digestive System Chapter 14 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. 2. 3. 4. 5. 6. Ingestion Physical Digestion Mechanical Digestion Propulsion Chemical Digestion Absorption 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 Chemical Digestion vs metabolism Chemical digestion occurs in system, then cells use nutrients for metabolism Anabolism- building up of molecules Catabolism- breaking down of molecules= hydrolysis Digestive System GI Tract (Alimentary Canal) Mouth Pharynx Esophagus Stomach Sm Intestine Lg Intestine Anus Accessory Organs Teeth Tongue Salivary Glands Liver Gall Bladder Pancreas Histology of GI tract wall Layers: Mucosa, submucosa, muscularis, serosa Lumen: opening/hollow center Membrane: peritoneum (visceral & parietal) Peritoneum- Membrane Visceral peritoneum Peritoneal cavity Parietal peritoneum Nutrition, Chemical Digestion and Metabolism Nutritional polymers broken down into monomers (or building blocks) during digestion …then metabolized proteins carbohydrates Nucleic acids lipids Carbohydrates monosaccharide Monosaccharide - glucose, fructose, galactose Disaccharides- lactose, maltose, sucrose Polysaccharidesstarches, cellulose, fiber, glycogen Energy source: pasta, bread, cellulose, sugar polysaccharides disaccharide Lipids Fats, Oils, Waxes, Cholesterol Insulation, membranes, energy diglyceride Fatty acids BAD FOR YOU Lipids (builds up in arteries & leads to heart disease) Saturated Fats: increase LDL (butter) Unsaturated Fats: decrease LDL (vegetable oils) Polyunsaturated Fats: Omega-3 ( nuts, fish oil, leafy greens) Proteins Tissue Maintenance and Growth, enzymes Amino acids (building blocks) dipeptide polypeptide Nucleic acids RNA DNA nucleotide sugar Digestive organ anatomy and physiology Oral Cavity Anatomy Teeth Tongue Cheeks Lips Hard and Soft Palates *Tonsils *Uvula Salivary glands- saliva Salivary Gland Secretion SALIVA •Contains enzyme called salivary amylase (starch breakdown) •chemically digests polysaccharide starches into disaccharides •Mumps (disorder) – swelling, pain of salivary glands Oral cavity physiology 1. Ingestion 2.& 3. Physical digestion •Mechanicalmastication by teeth, mashing by tongue •Propulsionswallowing by tongue 4. Chemical digestionsaliva contains enzymes (amylase) lips Pharynx anatomy and physiology 1. Physical •Propulsionswallowing, peristalsis Esophagus anatomy and physiology 1. Physical • Propulsionperistalsis •Heartburn (disorder) Stomach anatomy cardia Peptic ulcers H. pylori vomiting Microscopic stomach anatomy rugae 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 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 Digestive System Lab Liver anatomy Disorders: Jaundice (bilrubin), cirrhosis (scar) , hepatitis (swelling & inflammation) Liver anatomy Liver secretion •Produces bile which empties into duodenum of sm. intestine •contains H2O, bile salts, pigments, cholesterol, electrolytes, phospholipids •Bile salts emulsify fats into smaller fat droplets, but no enzymes 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 Gall bladder anatomy and physiology 1. Stores and releases excess bile from liver into duodenum Disorder: gallstones Pancreas anatomy and physiology 1. Chemical digestion- secretes pancreatic juice into duodenum, contains enzymes, (see next slide) Disorder: diabetes 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 Small Intestine anatomy Disorder: Lactose intolerance Small Intestine anatomy Containing lacteals and microvilli VILLI 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 Small Intestine physiology 1. & 2. Physical •Mechanicalsegmentation •Propulsionperistalsis, 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!!! Large Intestine anatomy Disorders: Flatulence, hemorrhoids, constipation, diarrhea 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 1 Physical Large Intestine physiology •Propulsionperistalsis and defecation reflex 2. Chemical??-by bacteria, (see previous slide) 3. Absorption of H2O!!!! electrolyteshepatic portal circulation to liver 4. Defecation 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 Overview of physiologychemical 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