HUN 1201 22 October 2014 Exam 2 Study Guide 1 Define hunger and appetite Which organ triggers feelings of hunger and o Hunger the physiological drive for food that occurs when the body senses that we satiation need to eat Nonspecific Can be satisfied by a variety of foods o Appetite a psychological desire to consume specific foods Aroused by environmental cues i e seeing pizza on TV and then being hungry for pizza 2 What effect do different macronutrients have on hunger What type of food has the highest satiation value o Macronutrients such as proteins fats and carbs make us feel full o Protein makes us feel full longer therefore it has the highest satiety value High fat diets have a higher satiety value than high carbohydrate values Bulky meals high in fiber and water distend the stomach and promotes a sense of satiety Solid foods are more filling than semisolid foods or liquids 3 Define the processes of digestion absorption and elimination o Digestion large food molecules are broken down to smaller molecules mechanically and chemically o Absorption process of taking the smaller molecules broken down during digestion through the intestinal wall Elimination undigested portions of food and waste products are removed from the body o 4 Know the difference between peristalsis and segmentation o o o Peristalsis waves of squeezing and pushing contractions that move food chime and feces in one direction through the length of the GI tract Segmentation rhythmic contraction of circular muscles in the intestinal wall that mixes the chime and enhances its contact with digestive enzymes and enterocytes The main difference between the two is that segmentation is a muscle contraction that aids more in actual digestion breaking down whereas peristalsis is the muscle contraction that moves products along the GI Tract 5 Know the role of gastrin o Gastrin a hormone that is secreted by stomach lining cells that stimulates the gastric glands to produce gastric juice which contains enzymes to break down food 6 Know the two different types of cells in gastric glands Parietal cells secrete HCl hydrochloric acid and intrinsic factor o HCl has a pH of 1 0 which keeps the stomach lining very acidic the acidic environment in the stomach kills any bacteria and or germs that may have entered the body It also denatures proteins breaking their bonds Intrinsic factor is a protein crucial for the absorption of vitamin B12 o Chief cells secrete pepsinogen and gastric lipase Pepsinogen an inactive enzyme that HCl converts into the active enzyme pepsin which then starts the breakdown of protein It also activates many other GI enzymes that contribute to digestion 1 of HUN 1201 22 October 2014 juice Gastric lipase an enzymes that is responsible for lipid digestion only minimal digestion of lipids occurs in the stomach 7 What is gastric juice and what is the role of each component of the gastric o Gastric juice is the acidic liquid secreted within the stomach it contains hydrochloric acid pepsin and other compounds HCl has a pH of 1 0 which keeps the stomach lining very acidic the acidic environment in the stomach kills any bacteria and or germs that may have entered the body It also denatures proteins breaking their bonds Pepsinogen an inactive enzyme that HCl converts into the active enzyme pepsin which then starts the breakdown of protein It also activates many other GI enzymes that contribute to digestion 8 Know the role of bicarbonate in stomach and small intestine o Bicarbonate is secreted to neutralize chyme 9 Know the enzymes produced in gastrointestinal tract mouth stomach and pancreas that facilitate the digestion of carbohydrates fats and lipids Organ where produced Mouth Stomach Pancreas Enzyme Site of Action Primary Action Mouth Stomach Small intestine Salivary amiylase Pepsin Gastric lipase Proteases Elastase Pancreatic lipase Cholesterol esterase Pancreatic amylase Carboxypeptidase dipeptidase Lipase Sucrose maltase lactase Digests carbs Digests proteins Digests lipids Digests proteins Digests fibrous proteins Digests lipids Digests cholesterol Digests carbohydrates Digests proteins Digests lipids Digests simple carbs sucrose maltose lactose Small intestine Small intestine 10 List the key hormones involved in digestion and their actions Hormone Gastrin Production site Target organ Actions Stomach Stomach Stimulates secretion of HCL and pepsinogen inactive 2 of HUN 1201 22 October 2014 Secretin Small intestine duodenum Pancreas Stomach Cholecystokinin CCK Small intestine duodenum and jejunum Pancreas Gallbladder Stomach Gastric Inhibitory peptide GIP Small intestine Stomach Pancreas form of pepsin Stimulates gastric motility Promotes proliferation of gastric mucosal cells Stimulates the secretion of pancreatic bicarbonate which neutralizes the acidic chime Decreases gastric mobility Stimulates secretion of pancreatic digestive enzymes Stimulates gallbladder contraction Slows gastric emptying Inhibits gastric acid secretion Slows gastric emptying Stimulates insulin release 11 List the accessory organs that facilitate digestion and their roles o Accessory organs produce store and secrete enzymes and other chemicals that are involved in digestion gallbladder pancreas and the liver o Gallbladder stores bile which is a greenish fluid produced by the liver before released into the small intestine through the bile duct CCK Cholecystokinin is the enzyme that signals the gallbladder to release the bile Bile emulsifies lipids that are then dispersed into smaller globules and become more accessible to digestive enzymes o Pancreas produces holds and secretes digestive enzymes and bicarbonate which are released into the small intestine via the pancreatic duct Stores enzymes in the inactive form Pancreatic amylase digests carbohydrates Pancreatic lipase digests fats Protease digests proteins Insulin and glucagon two hormones are produced to regulate blood glucose Bicarbonate is secreted to neutralize chime o Liver one of the most important organs in the body synthesizes chemicals for metabolism Produces bile for emulsification of fats Receives the products of digestion via the portal vein Releases glucose from glycogen stores Manufactures blood proteins Stores vitamins Filters the blood removing wastes and toxins 12 Define food intolerance and food allergy 3 of HUN 1201 22 October 2014 o o o o Food intolerance gastrointestinal discomfort caused by certain foods that is not a result of an immune system reaction often
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