CHAPTER 12 Digestive System

Digestive System Overview Known as gastrointestinal tract Also known as digestive tract or alimentary canal Approximately 30 feet long Begins with mouth (oral cavity), ends with anus Functions Prepare foods for absorption into the bloodstream Prepare foods for use by the body cells Responsible for elimination of solid wastes from the body

Digestive System Structures Oral cavity (Buccal cavity) Lips Cheeks Hard palate Rugae Soft palate Uvula Tongue Principle organ of the sense of taste Also assists in process of chewing (mastication) and swallowing (deglutition)

Digestive System Structures Salivary glands Three pairs Parotids Submandibulars Sublinguals Secrete saliva Mostly water, but contains mucus and digestive enzymes that aid in digestive process Digestive enzymes contained in saliva Amylase – aids in digestion of carbohydrates Lipase – aids in digestion of fats

Digestive System Structures Pharynx Known as the throat Serves as passageway for both respiratory and digestive systems Oropharynx Section leading away from oral cavity Nasopharynx Behind nasal cavity Laryngopharynx Lower portion – opens into esophagus and larynx

Digestive System Structures Esophagus Receives food from pharynx and propels it to stomach Cardiac sphincter (lower esophageal sphincter) controls passage of food from esophagus into the stomach Relaxes = food enters stomach Contracts = stomach contents prevented from reentering the esophagus

Digestive System Structures Stomach Fundus Upper rounded portion Body Central part

Digestive System Structures Stomach Pylorus Lower tubular part (also called the gastric antrum) Pyloric sphincter regulates passage of food from stomach into the duodenum Folds in mucous membranes of stomach = Rugae

Digestive System Structures Stomach Gastric juices breakdown food in stomach Muscular action of stomach causes churning of food Mixes food with the secretions Chyme = liquidlike mixture of partially digested food and digestive secretions

Digestive System Structures Small intestine Approximately 20 feet long Also known as the small bowel Divided into three parts Duodenum Jejunum Ileum

Digestive System Structures Large intestine Cecum Appendix hangs from lower portion of cecum Ascending colon Hepatic flexure Transverse colon Splenic flexure Descending colon Sigmoid colon Rectum Anus

Accessory Organs of Digestion Liver Located immediately under diaphragm, slightly to the right Only digestive function Production of bile for emulsification of fats in small intestine

Accessory Organs of Digestion Liver Additional functions of liver Excretion of bile pigments into bile Synthesis of vitamin K-dependent plasma proteins Amino acid metabolism Carbohydrate metabolism Fat metabolism Phagocytosis Detoxification Storage of vital nutrients

Accessory Organs of Digestion Gallbladder Pear-shaped sac, located under surface of liver Main function: To store and concentrate bile produced by the liver Releases bile in response to presence of fatty content of food present in duodenum Emulsifies fats

Accessory Organs of Digestion Pancreas Located in upper left quadrant of abdomen, behind stomach Functions as exocrine gland to manufacture digestive juices Trypsin – breaks down proteins Pancreatic lipase – breaks down fats Pancreatic amylase – breaks down carbohydrates Sodium bicarbonate – neutralizes acidic stomach contents

Accessory Organs of Digestion Pancreas Functions as endocrine gland to manufacture insulin and glucagon Insulin – hormone that makes it possible for glucose to pass from blood through cell membranes to be used for energy Insulin also promotes conversion of excess glucose into glycogen Glucagon – hormone that stimulates the liver to convert glycogen into glucose in time of need

Accessory Organs of Digestion Teeth Primary responsibility Chewing (mastication) Food is ground by teeth and softened by saliva Primary teeth = deciduous teeth Set of 20 teeth – appears around age 6 months Secondary teeth = permanent teeth Begin to appear around age 6

Accessory Organs of Digestion Teeth Incisors Chisel shape with sharp edges for biting food Canine or cuspid teeth Useful for grasping and tearing food Bicuspids (premolars) and molars Flat surfaces, multiple projections for crushing and grinding food

Accessory Organs of Digestion Teeth Crown Visible part of the tooth Covered with enamel – hardest substance in body Neck Lies just beneath the gum line Root Embedded in bony socket of the jaw bone Root canal = pulp cavity Central core of the tooth

Accessory Organs of Digestion Layers of Teeth

Common Signs and Symptoms Achlorhydria Abnormal condition characterized by the absence of hydrochloric acid in the gastric juice Anorexia Lack or loss of appetite, resulting in the inability to eat

Common Signs and Symptoms Aphagia Condition characterized by the loss of the ability to swallow as a result of organic or psychologic causes Ascites Abnormal accumulation of fluid within the peritoneal cavity Fluid contains large amounts of protein and electrolytes

Common Signs and Symptoms Borborygmus An audible abdominal sound produced by hyperactive intestinal peristalsis Borborygmi are rumbling, gurgling, and tinkling noises heard when listening with a stethoscope

Common Signs and Symptoms Constipation Difficulty in passing stools, or an incomplete or infrequent passage of hard stools Diarrhea Frequent passage of loose, watery stools

Common Signs and Symptoms Dyspepsia Vague feeling of epigastric discomfort after eating Involves an uncomfortable feeling of fullness, heartburn, bloating, and nausea Dysphagia Difficulty in swallowing, commonly associated with obstructive or motor disorders of the esophagus

Common Signs and Symptoms Emaciation Excessive leanness caused by disease or lack of nutrition Emesis Material expelled from the stomach during vomiting Vomitus

Common Signs and Symptoms Eructation Act of bringing up air from the stomach with a characteristic sound through the mouth Belching Flatus; Flatulence Air or gas in the intestine that is passed through the rectum

Common Signs and Symptoms Gastroesophageal Reflux Backflow of contents of stomach into esophagus Often result of incompetence of the lower esophageal sphincter Icterus A yellowish discoloration of the skin, mucous membranes, and sclera of the eyes, caused by greater than normal amounts of bilirubin in the blood Also called jaundice

Common Signs and Symptoms Melena An abnormal, black, tarry stool containing digested blood Nausea Unpleasant sensation often leading to the urge to vomit Pruritus ani A common chronic condition of itching of the skin around the anus

Common Signs and Symptoms Steatorrhea Greater than normal amounts of fat in the feces Characterized by frothy, foul-smelling fecal matter that floats Vomit To expel the contents of the stomach through the esophagus and out of the mouth

PATHOLOGICAL CONDITIONS Digestive System

Achalasia Pronounced Defined (ak-al-LAY-zee-ah) Decreased mobility of the lower two-thirds of the esophagus along with constriction of the lower esophageal sphincter

Anal Fistula Pronounced Defined (AY-nal FISS-too-lah) Abnormal passageway in the skin surface near the anus usually connecting with the rectum May occur as the result of a draining abscess

Aphthous Stomatitis Pronounced Defined (AFF-thus stoh-mah-TYE-tis) Small inflammatory noninfectious ulcerated lesions occurring in the lips, tongue, and inside the cheeks of the mouth Also called canker sores

Appendicitis Pronounced Defined (ap-pen-dih-SIGH-tis) Inflammation of the vermiform appendix Usually an acute condition that can lead to rupture (perforation) with resultant inflammation of the peritoneum (peritonitis)

Celiac Disease Pronounced Defined (SEE-lee-ak disease) Nutrient malabsorption due to damaged small bowel mucosa

Cirrhosis Pronounced (sih-ROH-sis) Defined Disease of the liver that is chronic and degenerative causing injury to the hepatocytes (functional cells of the liver) Fat infiltrates lobules of the liver, causing tissue covering the lobes to become fibrous Functions of liver eventually deteriorate

Colorectal Cancer Pronounced Defined (koh-loh-REK-tal CAN-sir) Presence of a malignant neoplasm in the large intestine

Constipation Pronounced Defined (kon-stih-PAY-shun) A state in which the individual’s pattern of bowel elimination is characterized by a decrease in the frequency of bowel movements and the passage of hard, dry stools Individual experiences difficult defecation

Crohn’s Disease Pronounced Defined (KROHNZ dih-ZEEZ) Digestive tract inflammation of a chronic nature causing fever, cramping, diarrhea, weight loss, and anorexia

Dental Caries Pronounced Defined (DEN-tal KAIR-eez) Tooth decay caused by acid-forming microorganisms

Dysentery Pronounced Defined (DISS-en-ter-ee) A term used to describe painful intestinal inflammation typically caused by ingesting water or food containing bacteria, protozoa, parasites, or chemical irritants Person has frequent stools that often contain blood

Diverticular Disease Pronounced Defined (dye-ver-TIK-yoo-lar dih-ZEEZ) Expression used to characterize both diverticulosis and diverticulitis Diverticulosis = non-inflamed outpouchings or herniations of the muscular layer of the intestines, typically the sigmoid colon Diverticulitis = inflammation of these outpouchings

Esophageal Varices Pronounced Defined (eh-soff-ah-JEE-al VAIR-ih-seez) Swollen, twisted (tortuous) veins located in the distal end of the esophagus

Gallstones (Cholelithiasis) Pronounced (koh-lee-lih-THIGH-ah-sis) Defined Pigmented or hardened cholesterol stones formed as a result of bile crystallization

Hemorrhoids Pronounced Defined (HEM-oh-roydz) Hemorrhoid is an unnaturally distended or swollen vein (varicosity) in distal rectum or anus

Hepatitis Pronounced Defined (hep-ah-TYE-tis) Acute or chronic inflammation of the liver due to a viral or bacterial infection, drugs, alcohol, toxins, or parasites

Hernia Pronounced Defined (HER-nee-ah) Irregular protrusion of tissue, organ, or a portion of an organ through an abnormal break in the surrounding cavity’s muscular wall

Herpetic Stomatitis Pronounced Defined (her-PEH-tic stoh-mah-TYE-tis) Inflammatory infectious lesions in or on the oral cavity occurring as a primary or a secondary viral infection caused by herpes simplex

Hirschsprung’s Disease (Congenital Megacolon) Pronounced (HIRSH-sprungz dih-ZEEZ) (kon-JEN-ih-tal meg-ah-KOH-lon) Defined Absence at birth of the autonomic ganglia in a segment of the intestinal smooth muscle wall that normally stimulates peristalsis

Ileus Pronounced Defined (ILL-ee-us) Obstruction of the intestine May occur due to twisting of the bowel, absence of peristalsis, or presence of adhesions or tumor

Intestinal Obstruction Pronounced (in-TESS-tin-al ob-STRUCK-shun) Defined Complete or partial alteration in the forward flow of the contents in the small or large intestines

Intussusception Pronounced Defined (in-tuh-suh-SEP-shun) Telescoping of a portion of proximal intestine into distal intestine usually in the ileocecal region causing an obstruction Typically occurs in infants and young children

Irritable Bowel Syndrome Spastic Colon Pronounced (EAR-it-ah-b’l BOW-el SIN-drom) (SPAS-tik COH-lon) Defined Increased motility of the small or large intestinal wall resulting in abdominal pain, flatulence, nausea, anorexia, and the trapping of gas throughout the intestines

Oral Leukoplakia Pronounced Defined (OR-al loo-koh-PLAY-kee-ah) Precancerous lesion occurring anywhere in the mouth

Pancreatitis Pronounced Defined (pan-kree-ah-TYE-tis) Acute or chronic destructive inflammatory condition of the pancreas May be acute or chronic

Peptic Ulcers (Gastric, Duodenal, Perforated) Pronounced (PEP-tik ULL-sir) (GAS-tric, doo-oh-DEE-nal, PER-foh-ray-ted) Defined Break in the continuity of the mucous membrane lining of the gastrointestinal tract as a result of hyperacidity or the bacterium, Helicobacter pylori

Peptic Ulcers Peptic ulcer descriptions Symptoms of an ulcer Acute or chronic Singular or clustered Shallow or deep Symptoms of an ulcer Gnawing epigastric pain Heartburn or indigestion Nausea and vomiting Bloated feeling after eating

Periodontal Disease Pronounced Defined (pair-ee-oh-DON-tal dih-ZEEZ) Group of inflammatory gum disorders May lead to degeneration of teeth, gums, and sometimes surrounding bones

Polyps, Colorectal Pronounced Defined (PALL-ips koh-loh-REK-tal) Small growths projecting from the mucous membrane of the colon or rectum May be sessile (attached by a base) or pedunculated (attached by a stalk) May vary in size and may be benign or pre-cancerous

Thrush Pronounced Defined (THRUSH) Fungal infection in the mouth and throat producing sore, creamy white, slightly raised curdlike patches on the tongue and other oral mucosal surfaces Caused by Candida albicans

Ulcerative Colitis Pronounced Defined (ULL-sir-ah-tiv koh-LYE-tis) Chronic inflammatory condition resulting in a break in the continuity of the mucous membrane lining of the colon in the form of ulcers Characterized by large watery diarrheal stools containing mucus, pus, or blood

Volvulus Pronounced Defined (VOL-vyoo-lus) Rotation of loops of bowel causing a twisting on itself that results in an intestinal obstruction

DIAGNOSTIC TECHNIQUES, TREATMENTS AND PROCEDURES Digestive System

Diagnostic Techniques, Treatments, and Procedures Abdominal ultrasound High-frequency sound waves to provide visualization of the internal organs of the abdomen (liver, gallbladder, bile ducts, pancreas, kidneys, bladder, and ureters) Abdominocentesis (Paracentesis) Insertion of a needle or trochar into abdominal cavity to remove excess fluid Person is in a sitting position

Diagnostic Techniques, Treatments, and Procedures Alanine Aminotransferase (ALT) Hepatocellular enzyme released in elevated amounts due to liver dysfunction Also known as serum glutamic pyruvic transaminase (SGPT)

Diagnostic Techniques, Treatments, and Procedures Alkaline Phosphatase (ALP) Enzyme found in highest concentrations in liver, biliary tract, and bone Amylase Enzyme secreted normally from pancreatic cells that travels to the duodenum by way of pancreatic duct Aids in digestion

Diagnostic Techniques, Treatments, and Procedures Appendectomy Surgical removal of an inflamed appendix May be removed via laparoscope if no rupture has occurred

Diagnostic Techniques, Treatments, and Procedures Barium Enema (BE) Infusion of a radiopaque contrast medium, barium sulfate, into the rectum and held in the lower intestinal tract while x-ray films are obtained of the lower GI tract

Diagnostic Techniques, Treatments, and Procedures Barium Swallow (Upper GI Series) Involves oral administration of a radiopaque contrast medium, barium sulfate, which flows into the esophagus as the person swallows

Diagnostic Techniques, Treatments, and Procedures Cheiloplasty Surgically correcting a defect of the lip Cholecystectomy Surgical removal of the gallbladder Cholecystography (Oral) Visualization of the gallbladder through x-ray following the oral ingestion of pills containing a radiopaque iodinated dye

Diagnostic Techniques, Treatments, and Procedures Colonoscopy Visualization of the lining of the large intestine using a fiberoptic colonoscope Colostomy Surgical creation of a new opening on the abdominal wall through which the feces will be expelled, by bringing the incised colon out to the abdominal surface Abdominal-wall anus

Diagnostic Techniques, Treatments, and Procedures CT of the abdomen Painless, noninvasive x-ray procedure Produces an image created by the computer representing a detailed cross section of the tissue structure within the abdomen Computerized tomography (CT) of the abdomen

Diagnostic Techniques, Treatments, and Procedures Endoscopic Retrograde Cholangiopancreatography Examines the size of and filling of the pancreatic and biliary ducts through direct radiographic visualization with a fiberoptic endoscope

Diagnostic Techniques, Treatments, and Procedures Esophagogastroduodenoscopy (EGD) Process of direct visualization of the esophagus, stomach, and duodenum using a lighted, fiberoptic endoscope Also known as an upper endoscopy

Diagnostic Techniques, Treatments, and Procedures Extracorporeal Shock Wave Lithotripsy (ESWL) Alternative treatment for gallstones by using ultrasound to align the computerized lithotripter and source of shock waves with the stones To crush the gallstones and thus enable the contraction of the gallbladder to remove stone fragments

Diagnostic Techniques, Treatments, and Procedures Fluoroscopy Radiological technique used to examine the function of an organ or a body part using a fluoroscope Gastric analysis Study of the stomach contents to determine the acid content and to detect the presence of blood, bacteria, bile, and abnormal cells

Diagnostic Techniques, Treatments, and Procedures Gastric Lavage Irrigation, or washing out, of the stomach with sterile water or a saline solution

Diagnostic Techniques, Treatments, and Procedures Herniorrhaphy Surgical repair of a hernia by closing the defect using sutures, mesh, or wire Liver biopsy Piece of liver tissue obtained for examination by inserting a specially designed needle into the liver through the abdominal wall

Diagnostic Techniques, Treatments, and Procedures Liver scan Noninvasive scanning technique Enables visualization of shape, size, and consistency of liver after IV injection of a radioactive compound Magnetic Resonance Imaging (MRI) Noninvasive scanning procedure that provides visualization of fluid, soft tissue, and bony structures without the use of radiation

Diagnostic Techniques, Treatments, and Procedures Nasogastric intubation Placement of a tube through the nose into the stomach To relieve gastric distension by removing gastric secretions, gas, or food

Diagnostic Techniques, Treatments, and Procedures Percutaneous Transhepatic Cholangiography (PTC) or (PTHC) Examination of bile duct structure using a needle to pass directly into an intrahepatic bile duct to inject a contrast medium

Diagnostic Techniques, Treatments, and Procedures Serum Bilirubin Measurement of bilirubin level in serum Serum bilirubin levels are a result of the breakdown of red blood cells Serum Glutamic-oxaloacetic Transaminase (SGOT) Enzyme that has very high concentrations in liver cells Also known as aspartate aminotransferase (AT)

Diagnostic Techniques, Treatments, and Procedures Small bowel follow-through Oral administration of a radiopaque contrast medium, barium sulfate Flows through the GI system X-ray films are obtained at timed intervals to observe the progression of the barium through the small intestine

Diagnostic Techniques, Treatments, and Procedures Stool analysis for occult blood Analysis of a stool sample to determine presence of blood not visible to naked eye Stool culture Collection of a stool specimen placed on one or more culture mediums Allowed to grow colonies of microorganisms to identify specific pathogen(s)

Diagnostic Techniques, Treatments, and Procedures Stool Guaiac Test on a stool specimen using guaiac as a reagent Identifies presence of blood in stool Urinary Bilirubin Tests for conjugated or direct bilirubin in a urine specimen