Bài giảng Medical Assisting - Chapter 31: The Digestive System

Objectives 31-1 Spell, define, and correctly use the Key Terms in this chapter. 31-2 List the functions of the digestive system. 31-3 Trace the pathway of food through the alimentary canal. 31-4 Describe the structure and functions of the mouth, teeth, tongue, and salivary glands. 31-5 Describe the structure and function of the pharynx.

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ChapterPowerPoint® to accompany Second EditionRamutkowski  Booth  Pugh  Thompson  WhickerCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Medical Assisting Chapter 311Objectives31-1 Spell, define, and correctly use the Key Terms in this chapter.31-2 List the functions of the digestive system.31-3 Trace the pathway of food through the alimentary canal.31-4 Describe the structure and functions of the mouth, teeth, tongue, and salivary glands.31-5 Describe the structure and function of the pharynx.The Digestive System2Objectives (cont.)31-6 Describe the swallowing process.31-7 Describe the structure of the esophagus and tell how it propels food into the stomach.31-8 Describe the structure and functions of the stomach.31-9 List the substances secreted by the stomach and give their functions.31-10 Describe the structure and functions of the small intestine.The Digestive System331-11 List the substances secreted by the small intestine and describe the importance of each.31-12 Explain the structures and functions of the liver, gallbladder, and pancreas.31-13 List the substances released by the liver, gallbladder, and pancreas into the small intestine and give the function of each secretion.The Digestive SystemObjectives (cont.)431-14 Describe the structure and functions of the large intestine.31-15 Tell what types of nutrients are absorbed by the digestive system and where they are absorbed.31-16 Describe the signs, symptoms, causes, and treatments of various disorders and diseases of the digestive system.The Digestive SystemObjectives (cont.)5Introduction Digestion The mechanical and chemical breakdown of foods into forms that your body cells can absorb The organs of the digestive system carry out digestion.Two categories Those of the alimentary canal The accessory organs 6Alimentary Canal Mucosa - absorbs nutrientsSubmucosa - carry away absorbed nutrientsMuscular layer - move materials through the canalSerosa - secretes serous fluid to keep the outside of the canal moist and prevent it from sticking to other organs. Length of the entire canal is about 9 meters (29 feet)7Mouth, Teeth, Tongue, and Salivary Glands Mouth takes in food and reduces its size through chewing Salivary glands - saliva (spit) contains an enzyme that will break down carbohydrates Teeth act to decrease the size of food particles and different types of teeth are adapted to handle food in different ways8Apply Your KnowledgeWhat is the purpose of the serosa?9Apply Your Knowledge -Answer Serosa - secretes serous fluid to keep the outside of the alimentary canal moist and prevent it from sticking to other organs.What is the purpose of the serosa?10PharynxThe throat - long, muscular structure that extends from the area behind the nose to the esophagus Nasopharynx Oropharynx Laryngopharynx Acts to connect the nasal cavity with the oral cavity for breathing through the nose Acts to push food into the esophagus 11Swallowing Process An involuntary automatic response (reflex) Soft palate raises causing the uvula to cover the opening between the nasal cavity and oral cavity Epiglottis covers the opening of the larynx 12Swallowing Process (cont.)Muscles in the pharynx contract, forcing food toward the esophagus Esophagus opens Food is pushed into the esophagus by the muscles of the pharynx 13Esophagus Esophagus is a muscular tube about 25 cm long that connects the pharynx to the stomach Esophageal sphincter controls the movement of food into the stomach Opens and closes to allow or prevent movement of substances out of a tube 14StomachBelow the diaphragm in the upper left region of the abdominal cavity It functions to receive food from the esophagusMix food with gastric juice (secretions of the stomach lining) Start protein digestion Move food into the small intestineClick for Larger View15Stomach (cont.)16Stomach Secretions When a person smells, tastes, or sees appetizing food, the parasympathetic nervous system stimulates the gastric glands to secrete their products. Gastrin, made by the stomach, also stimulates gastric glands to become active. Chief cells - secrete pepsinogen, which becomes pepsin in the presence of acid. Pepsin digests proteins.17Stomach Secretions (cont.)Parietal cells –secrete hydrochloric acid, that convert pepsinogen to pepsin. secrete intrinsic factor, which is necessary for vitamin B12 absorption.18Small Intestine Small intestine is a tubular organ that extends from the stomach to the large intestine Carries out most digestion in the body and is responsible for absorbing most of the nutrients into the bloodstream 19Small Intestine - Secretions Peptidases - enzymes that digest proteins.Intestinal lipase - an enzyme that digests fats Sucrase, maltase, and lactase - Digest sugars. If a person cannot produce lactase, he will not be able to digest lactose, which is the sugar in dairy products - lactose intolerance20Apply Your KnowledgeYour patients states that she is lactoseintolerant. What does that mean?21Apply Your Knowledge -Answer She cannot produce lactase and cannot digest lactose, which is the sugar in dairy products; thus, she is lactose intolerant.Your patient states that she is lactoseintolerant. What does that mean?22Pancreas Pancreatic amylase - digests carbohydrates Pancreatic lipase - digests lipids Nucleases - digests nucleic acidsTrypsin, chymotrypsin, and carboxypeptidase - digest proteinsPancreas is located behind the stomach. Pancreatic acinar cells produce pancreatic juice.Pancreatic juice contains the following enzymes:23LiverReddish-brown in colorLarge organ that fills most of the upper right abdominal quadrant Has a large right lobe and a small left lobe - separated into smaller divisions called hepatic lobules. Hepatic lobules contain macrophages that destroy bacteria and viruses in the bloodStores vitamins and iron24Liver (cont.)Each hepatic lobule contains many cells called hepatocytes Process the nutrients in blood and make bile, which is used in the digestion of fatsBile leaves the liver through the hepatic duct25GallbladderSmall sac-like structure located beneath the liverOnly function is to store bileCholecystokinin causes the gallbladder to release bile Gallbladder26Large Intestine Large intestine extends from the ileum of the small intestine to where it opens to the outside world as the anus27Large Intestine (cont.)Lining of the large intestine - secretes mucus to aid in the movement of substancesLarge intestine absorbs water and a few electrolytes from chyme; the left over forms feces28The Absorption of NutrientsNutrients are defined as necessary food substances and are absorbed in the small intestine Carbohydrate Proteins Lipids Vitamins Minerals Water 29Apply Your KnowledgeWhy can a person live without their gallbladder?30Apply Your Knowledge -AnswerIt’s only purpose is to store bile. As long as a person is still making bile in the liver, they can still digest fats.Why can a person live without their gallbladder?31Diseases and Disorders of the Digestive SystemAppendicitis - an inflammation of the appendix Causes Blockage of appendix with feces Blockage of appendix with tumorTreatments Surgery to remove appendix Antibiotics to prevent infectionSigns and symptoms – lack of appetite, pain in and around the navel area or in the abdomen, nausea, slight fever, pain in the right leg, and increased white blood cell content32Diseases and Disorders of the Digestive SystemCirrhosis - a long lasting liver disease in which normal liver tissue is replaced with nonfunctional scar tissue Causes - Excessive alcohol consumptionHepatitis C infectionHepatitis B infection Treatment - Liver transplantLifestyle changes to stop medications or use of alcohol33Diseases and Disorders of the Digestive System (cont.)Colitis - defined as inflammation of the large intestineCauses - caused by viral or bacterial infection or the use of antibiotics. Ulcers in the large intestine, Crohn’s disease, various other diseases, and stress may contribute.TreatmentsTreating underlying causesChanging antibioticsFluidsRepair of ulcers34Colorectal cancer usually comes from the lining of the rectum or colon. Causes - mostly unknown. Polyps in colon or rectum can become cancerous.Signs Changes in bowel movementBlood in fecesAnemiaAbdominal painWeight lossNarrow fecesDiseases and Disorders of the Digestive System (cont.)35Crohn’s disease - a common type of inflammatory bowel disease and is an autoimmune disorder that typically affects the end of the small intestineCauses - this is an autoimmune disorder.TreatmentMedications to reduce inflammationAntibiotics Surgery to remove affected part of intestineChanges in diet Diseases and Disorders of the Digestive System (cont.)36Diverticulitis - inflammation of diverticuli in the intestine. Diverticuli are abnormal dilations in the intestinal wallCauses – mostly unknown. Lack of fiber in diet and bacterial infection of the diverticuli.SignsAbdominal painConstipationDiarrhea & nauseaFeverBlood in fecesHigh white blood cell countDiseases and Disorders of the Digestive System (cont.)37Gastritis - an inflammation of the stomach lining Causes - bacteria or viruses, some medications, alcohol, spicy foods, excessive eating poisons, and stress.TreatmentCook food properly to kill bacteria/virusesAvoid foods/medications that irritate stomach liningsBegin acid reducing medicationsDiseases and Disorders of the Digestive System (cont.)38Heartburn - called gastroesophageal reflux disease (GERD) - occurs when stomach acids are pushed into the esophagusCauses – alcohol, some foods, defective esophageal sphincter, pregnancy, obesity, hiatal hernia, and repeated vomiting. TreatmentReducing weightDiet changesReduce alcohol consumptionMedicationsNot lying down after mealDiseases and Disorders of the Digestive System (cont.)39Hemorrhoids - varicose veins of the rectum or anus Causes – constipation, excessive straining during bowel movements, liver disease, pregnancy, and obesity.TreatmentEating high fiberStool softenersMedicationsSurgeryDiseases and Disorders of the Digestive System (cont.)40Hepatitis - inflammation of the liver. Causes - bacteria, viruses, parasites, immune disorders, the use of alcohol and drugs, and overdose of acetaminophen.TreatmentAvoid drugs and alcoholPrescribed medicationsDiseases and Disorders of the Digestive System (cont.)41Hiatal hernia - occurs when a portion of the stomach protrudes into the chest through an opening in the diaphragm. Inguinal hernias - occurs when a portion of the large intestine protrudes into the inguinal canal.Oral cancer - usually involves the lips or tongue, but can occur anywhere in the mouth.Pancreatic cancer – 4th leading cause of death in the U.S.Stomach cancer - most common in the upper part of the stomach.Stomach ulcers - occur in the lining of the stomachDiseases and Disorders of the Digestive System (cont.)42Apply Your KnowledgeYour patient has been diagnosed with Crohn’s disease. What is the usual treatment for this disease?43Apply Your Knowledge -AnswerTreatment for Crohn’s disease includes medications to reduce inflammation, antibiotics, surgery to remove affected part of intestine and/or changes in diet Your patient has been diagnosed with Crohn’s disease. What is the usual treatment for this disease?44Summary Medical AssistantKnowledge of the digestive system will assist you in providing care for the patient with diseases and disorders of the digestive system. 45End of ChapterEnd of Chapter 46
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