Nutrition ch 3-6

Nutrition ch 3-6 - Ch 3 The Basics of Digestion Appetite...

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Ch. 3: The Basics of Digestion Appetite : the physiological desire to eat or drink Hunger : the physiological need for food Satiety : the sensation that you feel when you have had enough to eat. It determines how long you will go between meals and/or snacks. Proteins have the highest satiety value and carbohydrates have the lowest satiety value Sounds in the stomach does not indicate hunger Digestion Digestion : the breaking down of foods into absorbable components in the GI tract Components of the Digestive Tract : the mouth, esophagus, stomach, small and large intestines, and other organs 2 Forms of Digestion o Mechanical: involves chewing, grinding, and breaking food apart in the mouth so that it can be comfortably swallowed. Mixing with saliva and juices to soften food o Chemical: involves using digestive juices and enzymes to break down food into absorbable nutrients that are small enough to enter the cells of the GI tract, blood, or lymph tissues Esophagus Lower esophageal sphincter (LES): a circular band of muscle between the esophagus and the stomach that opens and closes to allow food to enter the stomach Heartburn : when the LES does not close and hydrochloric acid from the stomach goes back into the esophagus and irritate the lining GERD (gastroesophageal reflux disease): chronic heartburn and the reflux of stomach acids Stomach Continues mechanical digestion by churning and contracting to mix food with digestive juices. Hydrochloric acid (HCI): a powerful acid made in the stomach that has digestive functions. It also help kill microorganisms and lowers the pH in the stomach Gastrin: hormones produced in the stomach to aid digestion Pyloric Sphincter : between the stomach and the small intestine. It controls the flow of chime Small Intestine The primary organ for digestion and absorption within the body. Villi: finger like projections on the walls of the small intestine that mix the partially digested chyme with intestinal secretions
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Microvilli: smaller finger like projections that cover villi and maximize nutrient absorption. They increase the surface area of the small intestine Large Intestine Ileocecal sphincter: the gateway from the small intestine to the large intestines and it prevents backflow of fecal contents from the large intestine into the ileum By the time food enters the large intestine, it has been digested and the majority of the nutrients have been absorbed. Segments of the large intestine o Rectum : where stool is stored o Anus: connected to the rectum Accessory Organs Liver o Makes bile o Contains nutrient rich blood o Stores vitamins and minerals Gallbladder o Attached to the liver o Concentrates and stores bile Pancreas o Makes enzymes, hormones, insulin, glucagons and digestive enzymes. o
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This note was uploaded on 12/13/2010 for the course BIO 118 taught by Professor Brooks during the Spring '09 term at Delgado CC.

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Nutrition ch 3-6 - Ch 3 The Basics of Digestion Appetite...

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