HUN 1201 Fall 2011 Exam II Study Guide Chapter 3 1 What is the difference between hunger and appetite Hunger is the need for food Appetite is the want for specific food 2 What are the roles of each of the following in digestion a Hypothalamus triggers feeling of hunger and satiation located above b Sphincters muscles that control the passage of food material from the pituitary gland one GIT organ to the next c Taste and Olfactory Receptors detect distinct tastes Bitter sweet salty sour and umami obfactory receptors are detect aroma of food d Epiglottis covers the opening to the trachea windpipe during 3 What is the order of organs in the digestive tract swallowing Mouth Esophagus Stomach Small intestine Large intestine 4 Define the following and know where they occur a Peristalsis Peristalsis is the muscular contractions that move food through the GI tract b Segmentation Rhythmic contraction of circular muscles in the intestinal wall Mixes the chyme and enhances its contact with digestive enzymes and enterocytes c Haustration are segmentations in the colon that contract sluggishly to move contents 5 What are the components of gastric juice What role does each play a Hydrochloric acid HCl denatures proteins and activates pepsin b Pepsin enzyme to digest protein c Gastric lipase enzyme to digest fat d Intrinsic factor protein to absorb vitamin B12 a hormone secreted by stomach lining cells that stimulates the gastric glands to produce gastric juice Gastrin Gastric Glands Parietal Cells secrete HCl and intrinsic factor Chief Cells secrete pepsinogen and gastric lipase 6 What are the functions of chyme mucus and bicarbonate in the stomach Chyme liquid product of mechanical and chemical digestion in the stomach Mucus layer protects the stomach lining from the acid in gastric juices Bicarbonate neutralizes the acid comes from pancreas before it goes to duodenum 7 What are the 3 sections of the small intestine Duodenum jejunum ileum 8 What are the major functions of the large intestine Bacteria assist with final digestion Its main function is to store undigested food material and absorb water short chain fatty acids and electrolytes 9 Review the digestive enzymes and hormones of the GIT and their function 10 What are the three accessory organs and their functions Gallbladder stores bile CCK signals the gallbladder to release bile Panaceas Manufactures holds and secretes digestive enzymes stores enzymes in inactive form Insulin and glucagon hormones are produced to regulate blood glucose Bicarbonate is secreted to neutralize chyme Liver one of the most important organs Synthesizes chemicals for metabolism Bile for emulsification of fats Receives the products of digestion via the portal vein Releases glucose from glycogen stores Stores vitamins Manufactures blood protein Filters the blood removing wastes and toxins main storage for glycogen is in liver and muscles 11 Describe the absorptive surface of the GIT Mucosal membrane the lining of the GI tract has special structures to facilitate absorption Villi are folds in the lining that allow it to absorb more nutrients Enterocytes are absorptive cells in the villi Capillaries and a lacteal small lymph vessel are inside each villus The brush border is composed of microvilli which greatly increase the surface area 4 types of absorbtion Passive diffusion nutrients simply pass through the enterocytes and into the bloodstream without the use of a carrier or energy Facilitated diffusion requires a carrier protein Active transport requires energy and a protein carrier to transport nutrients Endocytosis pinocytosis active transport by which a small amount of intestinal contents is engulfed by the cell membrane into the cell Know the difference between hormones and enzymes Hormones Chemical messengers secreted into the bloodstream by endocrine glands to help regulate body functions Enzymes are complex chemicals that induce chemical changes in other substances to speed up bodily processes Carb digestion stops while in the stomach Fat transfers through lymph system Chapter 4 1 What is the difference between simple and complex carbohydrates Know examples and sources of each a Monosaccharides vs disaccharides b Oligosaccharides vs polysaccharides Simple carbohydrates c Contain one or two molecules d Commonly referred to as sugars Monosaccharides contain one molecule Glucose fructose and galactose Disaccharides contain two molecules Lactose maltose and sucrose enzymes that break them down are maltase lactase sucrose Complex carbohydrates Oligosaccharides contain 3 to 10 monosaccharides Most polysaccharides consist of hundreds to thousands of glucose molecules Starch glycogen most fibers 2 What is the difference between starch and glycogen Starch a Plants store carbohydrates as starch b Amylose straight chain of glucose c Amylopectin branched chain of glucose d Resistant starch fiber glucose molecules linked by beta bonds are largely indigestible Sources grains legumes fruits vegetables Glycogen Storage form of glucose for animals humans Not found in food and therefore not a source of dietary carbohydrate Stored in the liver and muscles 3 What is the difference between soluble and insoluble fibers Soluble fibers a Dissolve in water viscous and gel forming b Fermentable digested by intestinal bacteria c Associated with risk reduction of cardiovascular disease and type 2 diabetes d Examples pectin gum mucilage e Found in citrus fruits berries oats beans Insoluable Not water soluble nonviscous Cannot be fermented by bacteria in the colon Promote regular bowel movements alleviate constipation and reduce diverticulosis Examples lignins cellulose hemicelluloses Good sources whole grains seeds legumes fruits and vegetables 4 Where does carbohydrate digestion occur Which enzymes breakdown carbohydrates and where in the GIT Salivary amylase Enzyme that begins carbohydrate digestion in the mouth Breaks carbohydrates down to maltose Carbohydrate digestion does not occur in the stomach Most chemical digestion of carbohydrates occurs in the small intestine Pancreatic amylase Enzyme produced in the pancreas and secreted into the small intestine Digests carbohydrates to maltose Carb Digestion Additional enzymes in the microvilli digest disaccharides to monosaccharides Maltase Sucrase Lactase Monosaccharides are absorbed into the cells lining the small intestine and then enter the bloodstream 5 What happens to excess carbohydrates in the body Excess glucose is stored
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