Digestion and Absorption notes9-29.pdf
Digestion and Absorption notes9-29.pdf NUTR 400 01
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This 8 page Class Notes was uploaded by Madison Krasko on Thursday October 1, 2015. The Class Notes belongs to NUTR 400 01 at University of New Hampshire taught by in Summer 2015. Since its upload, it has received 216 views. For similar materials see Nutrition Health & Well Being in Biological Sciences at University of New Hampshire.
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Clutch. So clutch. Thank you sooo much Madison!!! Thanks so much for your help! Needed it bad lol
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Date Created: 10/01/15
Digestion and Absorption GI Tract 3 Major Functions: Digestion------ breaking down food small enough for body to use Absorption---- uptake of nutrients from GI tract to blood and lymph Elimination---- getting rid of waste/ unused material Major GI Tract organs: Mouth esophagus stomach small intestine large intestine rectum Accessory organs Salivary glands Pancreas Liver Gull bladder Structural organization Lumen----- space (tube) food passes threw surrounded by 4 layers of muscle. The 4 muscles: 1) mucosa--- -----epithelial tissue 2) submucosa---- provide structure, connective tissue 3) muscularis---- multiple layers muscle fiber 4) Serosa----------connective tissue, protects tube Movement of Material in GI Tract Neural and hormonal communication: GI tract Hypothalamus Hormones Sphincters -doorways made of circular bands of muscle that control movement from 1 part to another in the GI tract 1) lower esophageal= esophagus stomach, stops backsplash 2) pyloric= bottom of stomach small intestine 3) ileocecal= end of small intestine 4) rectal and anal GI Motility 1) peristalsis= wave-like motion of intestine that pushes food 2) segmentation= squeezing like action that constricts and relaxes. Mixes Secretions -made by cells within GI tract -lubricates GI tract -protects epithelial cells 1) saliva--- has enzymes (salivary amylase) that starts digesting carbs 2) mucus 3) hydrochloric acid and bicarbonate 4) enzymes---- proteins that speed up reactions How Does Digestion Get Started 1) Cephalic phase---- sensory experiences indicate food is coming. Releases hormones to tell GI tract to get ready 2) Mouth--- mechanical and chemical Swallowing -as bolus is swallowed, it goes into esophagus, there’s a flap that covers opening into lungs, then food goes into stomach through a sphincter. Stomach -rugae lets it fold and compress and expands into 2 liters -a holding vessel for food -makes gastric secretions Gastric Juices in Gastric Pits Gastrin Mucus Pepsinogen Hydrochloric acid Lipase GERD—gastro esophageal reflex disease -sphincter before stomach, main reason is to stop backwash into esophagus and avoid this continual heart burn and reflex needs to get fixed Peptic ulcers—family of ulcers. Erosions in mucosal lining in GI tract -gastric ulcers in stomach -duodenal ulcers -esophageal ulcers caused by: helicobacterpylori---- antibiotics= cure AFTER STOMACHPYLORIC SPHINCTER SMALL INTESTINE Bolus chime Intestinal phase begins: 1)Small intestine -10 ft long - three segments: A) duodenum B) jejunum C) ileum -major site of absorption NUTRIENTS GI TRACT BODY Absorption of nutrients -uptake of nutrients go to blood or lymph -villi in the small intestine stick out and increase surface area of intestine. Increase absorption -after absorption, nutrients travel via either cardiovascular system or lymphatic system Celiac Disease -autoimmune disease -inflammatory response to glutton -wheat, rye, barley -villi damaged, poor absorption 10-1-15 why is hydrochloric acid imp during digestion and absorption? Helps digest dietary protein Helps activate digestive enzymes Kills harmful pathogens consumed Key Accessory Organs -liver, gallbladder, pancreas, common bile duct. Liver-----------------------makes bile Gallbladder---------------stores bile.. can live without this Pancreas-----------------pancreatic enzymes, imp. For digestion of macronutrients . ----makes bicarbonate that mixed with chime from stomach, neutralize PH in small intestine Hormonal Regulation -movement of food in the duodenum causes this:: -CCK goes to the gallbladder and tells it to release bile. - goes to pancreas and tells it to release pancreatic enzyme. -stimulates liver to produce more bile -tells pancreas to release the bicarbonate Large intestine -reabsorbs water, salts for use by body tissues -intestinal microflora -sphincters -produces vitamin K and digests some fatty acids so we get them IBS & IBD -Irritable Bowel Syndrome -Irritable Bowel Disease -Ulcerative Colitis…… small intestine -Chon’s Disease……. Large intestine Carbohydrates -Most are plant-based foods -Make up the majority of our calories each day -From ½ to 2/3 comes from carbs Basics: -Energy yielding nutrient (4 calories per gram) -Organic -Simple vs. complex--- structure. Simple- smaller. Complex= macromolecules -Rich food sources: sugar, starch, and fiber Simple Carbohydrate -Include monosaccharide (single units) and disaccharides (3 or more units) Monosaccharide All ring structure, have 6 carbons 3 Main Forms: -glucose---- form of carb. That is in the blood. Blood sugar= glucose. Most abundant in the body -fructose--consume from fruits and veggies#1 way= high fructose corn syrup -galactose—not in diet, don’t eat on own. Comes from the molecule lactose Disaccharides -made when adding multiple monosaccharides 3 main forms: - multose= glucose+ glucose…… Found in starch - sucrose= glucose+ Fructose….. Table sugars - Lactose= gluctose+ galactose….Milk sugar Polysaccharides -complex carbs -100’s-1000’s glucose molecules pound together -digestible vs. indigestible. Some digestible, some not. -digestible bady can break it down and turn it to glucose. Digestible: -Starches and glycogen!! -body can break these down into glucose types of 2 digestible starches: -amylose and amylopectin Glycogen - digestible polysaccharide - but we don’t eat this. Its found in the human body- in our liver tissue and in the skeletal muscle - this is our storage form of glucose. - If we ever haven’t ate in awhile the body will use this stored glucose to give our body fuel. Indigestible polysaccharides -Dietary fiber…. Still considered healthy -insoluble--- doesn’t dissolve in water -soluble----- does dissolve in water - most foods are a mixture of insoluble and soluble -more structural, stringy parts of food are insoluble. Soluble is inside. EX: peal of apple= insoluble. Inside= soluble - insoluble helps strengthen GI tract - soluble helps -Functional Fiber 2) which is not a rich source of dietary carbohydrates? - whole wheat pasta - soda…………………….. 100% carb calories. ALL SUGER - steak………………….Answer- protein and fat. No carbs though - apple 3) starch and fiber are classified as: -alternative sweeteners -polysaccharides…………… Answer -refined carbs -monosaccharides 4) where is the human body is glucose scored? -Brain and liver -Skeletal muscle and pancreas -Gallbladder and spleen -Liver and skeletal muscle 5) which of the following carbs is not fully digestible? Amylose Amylopectin Glucose Fiber……. Answer Sweeteners -Nutritive (provide calories) vs. nonnutritive (don’t provide calories) (alternative sweeteners) -Sugars -sugar alcohols (in toothpaste)- still nutritive- they provide calories -put in small amounts. -Alternative Sweeteners -whole family of sweeteners, close to 0 calories per gram- so nonnutritive. -aim to be similar to taste of table sugar - aim to be safe and zero to no calories -ADI -acceptable daily intake