NTDT 200 Nutrition Concepts Exam I Study Guide Chapters 3 4 5 6 This document serves only as a guide to assist you in narrowing your study focus Any material discussed in class is fair game on exams This exam will also cover as far as we discuss on Monday of the PROTEIN chapter Chapter 3 Chyme definition p 72 when does it leave the stomach P 73 Chyme the semiliquid mass of partly digested food expelled by the stomach into the duodenum Chyme leaves the stomach when it is completely liquefied by gastric juices Sphincters names of 4 sphincters function p 71 72 74 Esophageal Allow passage from mouth to esophagus upper and prevents backflow from esophagus to mouth Prevents passage from esophagus to stomach lower cardiac and backflow from stomach to esophagus Pyloric allows passage from the stomach to small intestine prevents backflow from small intestine Illeocecal allows passage from small to large intestine prevents backflow from large intestine Function of crypts and goblets in small intestine Crypts the crevices between the microvilli they are tubular glands that secrete intestinal juices into the small intestine Goblets cells of the GI tract and lungs that secrete mucus Digestion begins in mouth p 70 During chewing teeth crush large pieces of food into smaller ones and fluids from food drink and salivary glands blend with the pieces to ease swallowing Carbohydrate digestion begins in the mouth Digestive pathway from mouth to colon summary p 76 Small intestine D J I p 72 10 ft long Duodenum Jejunum ileum muscles Peristalsis Segmentation p 72 GI tract is ringed with circular muscles Surrounding these are longitudinal When the rings relax the long muscles tighten and the tube bulges likewise when the rings tighten the long muscles relax and the tube constricts peristalsis pushes food along and comes at varying rates Segmentation circular muscles of the intestine rhythmically contract and squeeze their contents this mixes the chime and promote close contact with digestive juices and the absorbing cells before letting the contents move along slowly Digestive Enzymes their Major Actions chart p 76 Site of most nutrient absorption p78 Small intestine 3 types of diffusion Simple water and small lipids Facilitated water soluble vitamins need a specific carrier to help them across the membrane Active Transport glucose and amino acids move against the concentration gradient requiring energy Major absorption site p 78 microvilli Transportation p80 vascular lymph systems which nutrients are transported by each of these Vascular blood water soluble nutrients and smaller products of fat digestion to the liver Lymphatic larger fats molecules and fat soluble vitamins Has no pump the nutrients circulate between the cells and collect in tiny vessels Chylomicrons large fat protein Veins carries blood to from liver comes from where where does it go HPV HV p81 Hepatic portal vein branches into a network of capillaries collects blood from GI tract and conducts it to the liver Hepatic Vein collects blood from the liver and returns it to the heart Heart arteries capillaries in intestines hepatic portal vein capillaries in liver hepatic vein heart Probiotics health benefits definition p 83 Living microorganisms found in foods and dietary supplements that when consumed in sufficient quantities are beneficial to health Change the conditions in native bacterial colonies in the GI tract to benefit health Benefits include alleviating diarrhea constipation IBS ulcers allergies lactose intolerance infant colic and can enhance immune function protect against colon cancer Homeostasis p 84 example of negative feedback loop Homeostasis the maintenance of constant internal conditions Check powerpoint slide 74 2 systems responsible for digestive absorptive processes p 84 endocrine nervous systems why important The mere thought sight and smell of food can elicit a response from the systems As food travels through the GI tract it will stimulate or inhibit digestive secretions by way of messages from both hormones and nerve pathways The endocrine system regulates the digestive hormone release Nervous system is your subconscious actions promoting digestion Primary actions of GI hormones ie Gastrin HCL pancreas bicarb secretin CCK gall bladder pancreas p 85 Anatomy of the digestive tract and events that occur in each organ See other sheet Appendix function Located near the end of small intestine beginning of large intestine HCL uncoils pro enzymes break down PRO Stomach muscles 3 types strongest in gi tract Stores lymph cells Function of HCL Circular Diagonal Longitudinal pH concepts stomach small intestine after bicarb and pancreatic juices added pH the unit of measure expressing a substance s acidity or alkalinity The lower the pH the higher the H ion concentration and the stronger the acid A pH above 7 is alkaline or base a solution in which OH ions predominate Bile 8 Pancreatic juice 8 Saliva 7 Gastric juice 2 homeostasis concept Homeo same stasis staying Survival depends on body conditions staying the same If things change too far from norm the body must do something to bring it back to normal The maintenance of constant internal conditions such as blood chemistry temperature and blood pressure by the body s control systems A homeostatic system is constantly reacting to external forces to maintain limits set by the body s needs hormones where they come from function what they target Hormones chemical messengers They are secreted by a variety of glands in response to altered conditions in the body Each hormone travels tone or more specific target tissues or organs where it elicits a specific response to maintain homeostasis Gastrin a hormone secreted by cells in the stomach wall Target organ the glands of the stomach Response secretion of gastric acid Secretin a hormone produced by cells in the duodenum wall Target organ the pancreas Response secretion of bicarbonate rich pancreatic juice Cholecystokinin a hormone produced by cells of the intestinal wall Target organ the gallbladder Response release of bile and slowing of GI mobility The slowing of the digestive process helps to maintain a pace that allows all reactions to reach completion condensation hydrolysis Condensation a reaction in which two molecules combine to form a larger Hydrolysis the chemical breakdown of a compound due to reaction with molecule water Chapter 4 Hydrolysis condensation of CHO p 99 To make a disaccharide condensation links two
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