Chapter 3 Exam 2 Study Guide 1 Define hunger and appetite Which organ triggers the feelings of hunger and satiation a Hunger the physiological drive for food nonspecific i Can be satisfied by a variety of different foods b Appetite psychological desire to consume specific foods aroused by environmental cues c Hypothalamus triggers feelings of hunger of satiation fullness i Located above the pituitary gland and the brain stem in an area of the ii brain that regulates involuntary activities Integrates signals from nerve cells chemical messengers hormones and the types of food consumed d The role of nerve cells and hunger Special cells lining the stomach and small intestine detect changes in pressure which indicate whether the organ is empty or distended with food These cells then send signals to the hypothalamus Feeling full satiated results from signals from the stomach and a rise in blood glucose levels by hormones which are secreted from the endocrine gland 2 What are the roles of food type on hunger What type of food has the highest satiation value a Foods have different effects on our feelings of hunger b Proteins have the highest satiety value will feel satiated for longer c High Fat Diets have a higher satiety value than high carbohydrate diets d Bulky Meals high in fiber and water distend the stomach and promote a sense of satiety e Solid Foods are more filling than semisolid foods or liquids 3 Describe the processes of digestion absorption and elimination a Digestion large food molecules are broken down to smaller molecules mechanically and chemically Hunger and appetite work together to prepare the GI tracts for digestion The first thought of food nervous system stimulates the release of digestive juices i Begins in the mouth Chewing moistens the food and mechanically breaks it into smaller pieces exposes more surface area to digestive juices ii Saliva contains digestive juices secreted by the salivary gland in the mouth umami iii Taste Receptors detect distinct tastes bitter sweet salty sour and iv Olfactory Receptors detect aromas of foods b Absorption process of taking these products through the intestinal wall c Elimination Undigested portions of food and waste products are removed from the body 4 Know the difference between peristalsis and segmentation a Fun Fact The mass of food chewed and moistened in the mouth is called bolus This mass travels from the mouth to the stomach through the esophagus no digestion occurs in the esophagus b Peristalsis is the muscular contractions that move food through the GI tract i Due to the actions of circular muscles and longitudinal muscles that run along the entire GIT ii Pushes the contents from one area to the next c Segmentation Rhythmic contraction of circular muscles in the intestinal wall Mixes the chyme liquid product of mechanical and chemical digestion in the stomach and enhances its contact with digestive enzymes and enterocytes 5 Know the role of gastrin a Gastrin a hormone secreted by stomach lining cells that stimulates the gastric glands to produce gastric juice 6 Know the two different types of cells in gastric glands What is gastric juice and what is the role of each component of the gastric juice a Parietal Cells secrete HCL and intrinsic factor b Chief Cells secrete pepsinogen and gastric lipase c Gastric Juice contains HCL gastric acid that denatures proteins and activates pepsin Pepsin enzyme to digest protein gastric lipase enzyme to digest fat and intrinsic factor protein that absorbs vitamin B12 i Mucus Layer protects the stomach lining from the acid in gastric juices 7 Know the role of bicarbonate in stomach and small intestine a Bicarbonate in the stomach saliva neutralizes the acid b Bicarbonate in the pancreas is secreted to neutralize chyme 8 Know the enzymes produced in gastrointestinal tract mouth stomach and pancreas that facilitate the digestion of carbohydrates fats and lipids a Enzymes in Saliva Mouth i Salivary amylase begins starch digestion b Enzymes in the Stomach i Pepsin ii Gastric Lipase c Enzymes in the Pancreas stores enzymes in the inactive form i Pancreatic Amylase digests carbohydrates ii Pancreatic Lipase digests fats iii Protease digests proteins 9 List the key hormones involved in digestion and their actions a Stomach hormone Gastrin stimulates gastric glands to produce gastric juice b Pancreatic hormones Insulin and Glucagon maintain blood glucose levels Feeling full results from signals from the stomach and a rise in blood glucose c Other key hormones involved in digestion i Secretin ii Cholecystokinin Signals the gallbladder to release bile CCK iii Gastric Inhibitory Peptide GIP d Hormones with potential digestive roles Somatostatin and Ghrelin 10 List the accessory organs that facilitate digestion and their roles a Gallbladder Stores bile a greenish fluid produced by the liver CCK signals the gallbladder to release bile Bile emulsifies the lipids i Lipids are dispersed into smaller globules and become more accessible to b Pancreas Manufactures hold and secretes digestive enzymes See question digestive enzymes number 8 for enzyme details i Insulin and Glucagon are hormones produced to regulate blood glucose levels ii Bicarbonate is secreted to neutralize chyme c Liver One of the most important organs in the body i Synthesizes chemicals for metabolism bile for emulsification of fats ii Receives the products of digestion via the portal vein iii Releases glucose from glycogen stores iv Stores vitamins v Manufactures blood proteins vi Filters the blood removing wastes and toxins 11 Define food intolerance and food allergy a Food Intolerance is a cluster of GI symptoms gas pain diarrhea that occur following combustion of a particular food b Food Allergy is a hypersensitivity reaction of the immune system to a particular component usually a protein in a food Chapter 4 Carbohydrates 1 List the most common types of monosaccharaides and disaccharides a Monosaccharaides contain one molecule Glucose Fructose and Galactose b Disaccharides contain two molecules Lactose Maltose and Sucrose 2 What are the characteristics of glucose fructose and galactose a Glucose Most abundant sugar molecule in our diet good energy source b Fructose Sweetest natural sugar Found in fruit high fructose corn syrup c Galactose Does not occur alone in foods binds with glucose to form lactose 3 What are the monosaccharides that synthesize lactose maltose and sucrose a Lactose Galactose Glucose b Maltose Glucose
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