NUTRITION EXAM 2Exam 2 Esophagus***Swallowing- Moves food from mouth à stomachEpiglottisFlap-like structure that prevents food from entering the trachea - Covers the larynxStomachBolus passes the lower esophageal sphincter into the stomach- If sphincter malfunctions, causing reflux, this causes heartburnFunctions of the stomach1. hold and mix food****2. water some fat and ~20% alcohol absorbed3. Produces gastrin, pepsinogen & HCL4. Secretes gastric juice: made of HCL, pepsinogen HCl functions******5. Inactivates ingested proteins 6. Destroys bacteria in foods7. Dissolves dietary minerals for absorption 8. Converts pepsinogen to pepsin (protein digestion, active)***Important cells in the stomach• Parietal cells: Creates HCL and intrinsic factor• Chief cells: Creates gastric lipase- Mixing bolus with stomach secretions • Pyloric sphincter****- Controls the flow of chyme into theSI- BOLUS vs. CHYME: bolus forms when you mix with saliva, chyme is mixed with stomach secretions**Small IntestineDivided into 3 sections*** (order)1. Duodenum2. Jejunum3. ileum• Interior made up of circular folds (vili)and fingerlike projections (microvili)1. Increases the surface area 600 times • Digestion and absorption occurs here• Vili (“fingers”) are lined with Goblet cells: Produce mucus, Endocrine cells: Produce hormones and Enterocytes: Produce digestive enzymes and absorb nutrients - brush border of microvilli that are covered with glycocalyx***Liver, Gallbladder, and Pancreas • Liver**- Produces bile**- Synthesizes and stores nutrients**• Gallbladder- stores bile** • Pancreas- Produces sodium bicarbonate & digestive enzymesGI Hormones- Gastrin : release HCL and pepsinogen- CCK : pancreatic enzymes and bile from the gallbladder- Secretin : release of pancreatic bicarbonate- Gastric Inhibitory Peptide : limit the release of gastric juicesAbsorption in the SI****1. Passive diffusion : absorbs fats, minerals and water, concentration gradient forces the nutrient into absorptive cells2. Facilitated diffusion : need carrier proteins to shuttleNUTRITION EXAM 23. Active absorption : need a carrier protein and ATP4. Endocytosis : type of active absorption where compounds or liquids are engulfedMajor Sites of Absorption along GI TractLI: Na, K, fatty acids, Vitamin K, Biotin***Moving Nutrients Around the BodyCardiovascular system**- water-soluble nutrients & short/ medium fatty acid chains are absorbed directly into blood stream and travel directly to the Liver *****Lymphatic system***- Alternate route for large molecules, fat soluble vitamins, some proteins- Transported by lacteals to larger lymphatic vessels** Large Intestine• SI à LI through ileocecal valve**• 3 sections of the large intestine- Colon, rectum and anus • 5 sections of the colon- cecum, transverse colon, ascendingcolon, descending colon, sigmoid colon• 3 main functions****1. Houses bacterial floraIleocecal valve prevents bacteria from migrating into SIKeeps growth of pathogenic bacteria under control Synthesizes vitaminsAid in lactose digestionFerment fibers and starches2. Absorbs water and electrolytes3. Expels fecesCommon Digestive ProblemsHeartburn and GERD caused by?**- Burning sensation or sour taste in the back of the mouth, hoarseness, trouble swallowing, coughing, gagging, stomach content going back into espophagus (lower esophageal sphincter malfunctions)- Risk factors: Hiatal hernia, alcohol use, overweight, smoking, pregnancy- Treatment: Lifestyle changes and medication, antacids, H2 blockersUlcers- Very small erosion of the top layer of cells in the stomach or duodenum***a. Causes**i. H pylori & heavyuse of NSAID Mxb. Alcohol, smoking, and emotional stress c. Treatment: avoid large doses of NSAIDSs- Inflammatory Bowel Disease (IBD)***: Group of serious intestinal disease- Ulcerative colitis and Chrohn’s- NOT the same as IBSCarbohydrates (CHOs)• Main source of energy ( 4 kcals/gm)• 45-65% AMDR*****• Sugar, starch and fiber forms• Simple: mono/di***• Complex: starch**Monosaccharaides all 3***• 6 carbon configuration (hexose)****- Examples: glucose, fructose and galactose• 5 carbon configuration (pentose)- Examples: RNA and DNANUTRITION EXAM 2- body can make when needed- Monosaccharide derivate- Xylitol, mannitol, sorbitolDisaccharides• Chemical bonding of 2 monosaccharaides • Maltose (alcohol)**- Sucrose (table sugar)**- Lactose (milk products)**- People are unable to digestOligosaccharides• 3 to 10 single sugar units***- Raffinose (3 mono)- Stachyose (4 mono)- Found in: Cabbage, onions, broccoli,whole wheat, & legumes• Can not be digested by human enzymes• Metabolized by bacteriaPolysaccharides • many glucose molecules• Starch- Major digestible polysaccharide- Storage for plants & animals***- Glycogen- Storage for humans & animals****Fiber- indigestible due to beta bonds**Starch• 2 types of plant starch1. Amylose- Linear, unbranched, alpha 1-4 bonds2. Amylopectin- branched alpha 1-4 & alpha 1-6*Examples: potatoes, beans, bread, pasta***Digestive Enzymes for Starch• AmylaseSecreted from: mouth and pancreasDigests amylose at alpha 1-4 bonds**• Alpha-dextrinase- Secreted from: intestinal enzymes- Digests amylopectin at alpha 1-6** bondsWhat is the significance of more branches?**- Causes glucose levels to increase quicklyGlycogen• Liver stores for energy***• Muscles store for use in muscle and endurance activity*** Fiber*****• Total fiber- Occurs naturally• Functional fiber- added to foods• insoluble fiber- not dissolved in water• Soluble fiber- Dissolve in waterInsoluble & Soluble Fibers• Insoluble- small intestine, pass into large intestine- Cellulose- Hemicellulose- Lignin – only noncarb component of dietary fiber*****- Skin of veggies, whole grains, seeds of fruits• Soluble- Pectins- Gums- Mucilages- Oat bran, jams and jelliesHealth Benefits of Fiber***• Insoluble** Decreases intestinal transit time and constipationLowers risk for disease and colon cancer• Soluble** Lowers cholesterol and glucoseTotallynaturalNUTRITION EXAM 2Delays gastric emptyingAlternative (Non-Nutritive) Sweeteners• Saccharin (Sweet’N Low)***a. Not for cooking (bitter taste)• Aspartame (Equal)**a. Contains phenylalanine Alternative Sweeteners• Neotamea. Heat-stable, can be used in cooking• Acesulfamine K (Sunette)a. Can be used in baking and cooking• Sucralose (Splenda)**a. Can be used in cooking• Tagatose (Naturlose)a.