Exam 2 Study Guide

Exam 2 Study Guide - Chapter 3 Study Guide: 1. What is the...

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Chapter 3 Study Guide: 1. What is the difference between hunger and appetite? Hunger is a physiologic drive for food that occurs when the body senses that we need to eat. It is nonspecific and numerous foods could satisfy the need. Appetite is the psychological desire to consume specific foods, aroused by environmental cues that stimulate our senses. Eating dinner is a result of hunger, while appetite compels us to eat the delicious desert afterwards despite being full. Anorexia is have a physiologic need for food without any appetite occurring as a side effect from illness. Hunger and appetite work hand in hand. 2. What are the roles of each of the following in digestion? a. Hypothalamus This region of the brain tissue is responsible for prompting us to seek food. It triggers feelings of hunger or satiation by integrating signals from nerve cells in the body and hormones. Special cells line the stomach and report changes in pressure to the hypothalamus. Hormones are chemical messengers that are secreted into the bloodstream by one of the many endocrine glands of the body. Insulin and glucogon are produced by the pancreas and regulate blood glucose. Glucose is the body’s energy supply and it’s levels help regulate hunger. Neuropeptide Y and galanin stimulate food intake while leptin, CCK, and serotonin stimulate satiety. b. Sphincters Regulates the flow of food between the organs in the GI tract. They are tight muscular rings that are stimulated to open when a nerve signals that food is ready to pass into the next section. Esophageal sphincter, gastroesophageal sphincter, pyloric sphincter, ileocecal valve c. Chewing Before chewing, the cephalic phase works to prepare the GI tract for digestion by the nervous system stimulating the release of digestive juices. When chewing, our teeth mechanically break up the food while saliva from the salivary glands chemically breaks the food. Enzymes in saliva begin to break down carbs until they reach the stomach, where the enzymes are inactivated by the high acidity. Saliva contains bicarbonate, mucus, antibodies, amylases, and lysozyme. d. Taste and Olfactory Receptors Saliva helps us taste- chemicals broken down by saliva attach to chemoreceptors on the tongue, and depends significantly on the olfaction. Odors attach to mucus in the nose, which then reaches chemoreceptors. e. Epiglottis
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The epiglottis protects the trachea. This flap is normally open, until nerves signal it to close when food nears the back of the mouth, along with the soft palette lifting to protect the sinuses. When the epiglottis closes, the esophageal sphincter opens to allow food to enter. 3. What is the order of organs in the digestive tract? Mouth, esophagus, stomach(holds 6 fl oz when empty, 4 layers, crinkled
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Exam 2 Study Guide - Chapter 3 Study Guide: 1. What is the...

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