Medical Assisting Chapter 31 PowerPoint® to accompany Medical Assisting Chapter 31 Second Edition Ramutkowski  Booth  Pugh  Thompson  Whicker Chapter 31 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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.

The Digestive System Objectives (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 System Objectives (cont.) 31-11 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 System Objectives (cont.) 31-14 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.

Introduction Digestion Two categories 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

Alimentary Canal Length of the entire canal is about 9 meters (29 feet) Mucosa - absorbs nutrients Submucosa - carry away absorbed nutrients Muscular layer - move materials through the canal Serosa - secretes serous fluid to keep the outside of the canal moist and prevent it from sticking to other organs.

Mouth, 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 ways

Apply Your Knowledge What is the purpose of the serosa?

Apply Your Knowledge -Answer What is the purpose of the serosa? Serosa - secretes serous fluid to keep the outside of the alimentary canal moist and prevent it from sticking to other organs.

Pharynx The 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

Swallowing 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

Swallowing 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

Esophagus 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

Stomach Below the diaphragm in the upper left region of the abdominal cavity It functions to receive food from the esophagus Mix food with gastric juice (secretions of the stomach lining) Start protein digestion Move food into the small intestine Click for Larger View

Stomach (cont.)

Stomach 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.

Stomach Secretions (cont.) Parietal cells – secrete hydrochloric acid, that convert pepsinogen to pepsin. secrete intrinsic factor, which is necessary for vitamin B12 absorption.

Small 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

Small 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 intolerance

Apply Your Knowledge Your patients states that she is lactose intolerant. What does that mean?

Apply Your Knowledge -Answer Your patient states that she is lactose intolerant. What does that mean? She cannot produce lactase and cannot digest lactose, which is the sugar in dairy products; thus, she is lactose intolerant.

Pancreas Pancreas is located behind the stomach. Pancreatic acinar cells produce pancreatic juice. Pancreatic juice contains the following enzymes: Pancreatic amylase - digests carbohydrates Pancreatic lipase - digests lipids Nucleases - digests nucleic acids Trypsin, chymotrypsin, and carboxypeptidase - digest proteins

Liver Reddish-brown in color Large 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 blood Stores vitamins and iron

Liver (cont.) Each hepatic lobule contains many cells called hepatocytes Process the nutrients in blood and make bile, which is used in the digestion of fats Bile leaves the liver through the hepatic duct

Gallbladder Gallbladder Small sac-like structure located beneath the liver Only function is to store bile Cholecystokinin causes the gallbladder to release bile Gallbladder

Large Intestine Large intestine extends from the ileum of the small intestine to where it opens to the outside world as the anus

Large Intestine (cont.) Lining of the large intestine - secretes mucus to aid in the movement of substances Large intestine absorbs water and a few electrolytes from chyme; the left over forms feces

The Absorption of Nutrients Nutrients are defined as necessary food substances and are absorbed in the small intestine Carbohydrate Proteins Lipids Vitamins Minerals Water

Apply Your Knowledge Why can a person live without their gallbladder?

Apply Your Knowledge -Answer Why can a person live without their gallbladder? It’s only purpose is to store bile. As long as a person is still making bile in the liver, they can still digest fats.

Diseases and Disorders of the Digestive System Appendicitis - an inflammation of the appendix Causes Blockage of appendix with feces Blockage of appendix with tumor Treatments Surgery to remove appendix Antibiotics to prevent infection Signs 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 content

Diseases and Disorders of the Digestive System Cirrhosis - a long lasting liver disease in which normal liver tissue is replaced with nonfunctional scar tissue Causes - Excessive alcohol consumption Hepatitis C infection Hepatitis B infection Treatment - Liver transplant Lifestyle changes to stop medications or use of alcohol

Diseases and Disorders of the Digestive System (cont.) Colitis - defined as inflammation of the large intestine Causes - 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. Treatments Treating underlying causes Changing antibiotics Fluids Repair of ulcers

Diseases and Disorders of the Digestive System (cont.) Colorectal 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 movement Blood in feces Anemia Abdominal pain Weight loss Narrow feces

Diseases and Disorders of the Digestive System (cont.) Crohn’s disease - a common type of inflammatory bowel disease and is an autoimmune disorder that typically affects the end of the small intestine Causes - this is an autoimmune disorder. Treatment Medications to reduce inflammation Antibiotics Surgery to remove affected part of intestine Changes in diet

Diseases and Disorders of the Digestive System (cont.) Diverticulitis - inflammation of diverticuli in the intestine. Diverticuli are abnormal dilations in the intestinal wall Causes – mostly unknown. Lack of fiber in diet and bacterial infection of the diverticuli. Signs Abdominal pain Constipation Diarrhea & nausea Fever Blood in feces High white blood cell count

Diseases and Disorders of the Digestive System (cont.) Gastritis - an inflammation of the stomach lining Causes - bacteria or viruses, some medications, alcohol, spicy foods, excessive eating poisons, and stress. Treatment Cook food properly to kill bacteria/viruses Avoid foods/medications that irritate stomach linings Begin acid reducing medications

Diseases and Disorders of the Digestive System (cont.) Heartburn - called gastroesophageal reflux disease (GERD) - occurs when stomach acids are pushed into the esophagus Causes – alcohol, some foods, defective esophageal sphincter, pregnancy, obesity, hiatal hernia, and repeated vomiting. Treatment Reducing weight Diet changes Reduce alcohol consumption Medications Not lying down after meal

Diseases and Disorders of the Digestive System (cont.) Hemorrhoids - varicose veins of the rectum or anus Causes – constipation, excessive straining during bowel movements, liver disease, pregnancy, and obesity. Treatment Eating high fiber Stool softeners Medications Surgery

Diseases and Disorders of the Digestive System (cont.) Hepatitis - inflammation of the liver. Causes - bacteria, viruses, parasites, immune disorders, the use of alcohol and drugs, and overdose of acetaminophen. Treatment Avoid drugs and alcohol Prescribed medications

Diseases and Disorders of the Digestive System (cont.) Hiatal 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 stomach

Apply Your Knowledge Your patient has been diagnosed with Crohn’s disease. What is the usual treatment for this disease?

Apply Your Knowledge -Answer Your patient has been diagnosed with Crohn’s disease. What is the usual treatment for this disease? Treatment for Crohn’s disease includes medications to reduce inflammation, antibiotics, surgery to remove affected part of intestine and/or changes in diet

Medical Assistant Summary Knowledge of the digestive system will assist you in providing care for the patient with diseases and disorders of the digestive system.

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