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29 Cards in this Set
- Front
- Back
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What two medullary centers are involved with vomiting?
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1. vomiting center in the medulla 2. chemoreceptor trigger zone on the floor of the 4th ventricle
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What are causes of GI bleeding?
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- disease or trauma to the GI structures (peptic ulcers) - blood vessel abnormalities (esophageal varices, hemorrhoids) - disorders in blood clotting
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What is occult blood?
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hidden blood that can only be detected by chemical means, such as guaiac-based stool tests
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What is the function of the lower esophageal sphrincter (or gastroesophageal sphincter)?
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- normally the sphincter remains constricted to prevent reflux of gastric contents into the esophagus - during swallowing, there is receptive relaxation of the the lower esophageal sphincter, which allows easy propulsion of the esophageal contents into the stomach
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What are causes of dysphagia?
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- can be causes by altered nerve function (lesions of the CNS and stroke that involve the cranial nerves that control swallowing (V, IX, X, XII)) - disorders that produce narrowing of the esophagus (strictures, cancer, scleroderma)
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What is scleroderma?
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- an autoimmune disease that causes firbous replacement of tissues in the muscularis layer of the GI tract - an important cause of dysphagia
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What is achalasia?
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- when the lower esophageal sphincter fails to relax and food has difficult passing into the stomach, causing enlargement of the esophagus above the lower esohphageal sphincter - increased risk for aspiration of esophageal contents into the lungs when the person lies down
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What is an esophageal diverticulum?
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- an outpouching of the esophageal wall caused by a weakness of the muscularis layer - common complaints are that ood stops before it reaches the stomach, qurgling, belching, coughing, and foul-smellin breath - can cause esophagitis and ulceration
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What are Mallory-Weiss tears?
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longitudinal tears in the esophagus at the esophagogastric junction
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What can cause gastroesohpageal reflux?
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- a weak or incompetent lower esophageal sphincter - decreased clearance of the refluxed acid from the esophagus after it has occurred
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What is Barrett's esophagus?
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- squamous mucosa that normally lines the esophagus is gradually replaced by columnar epithelium resembling that in the stomach or intestines - associated with increased risk for dfevelopment of esophageal cancer
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What are the 2 types of esophageal cancers?
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1. squamous cell carcinoma - usually caused by alcohol and tobacco; usually occur in the middle and lower third of the esophagus 2. adenocarcinoma - usually found in the distal esophagus and may invade the adjacent upper part of the stomach; are more closely linked to esophageal refulx and Barrett's esophagus
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What is the gastric mucosal barrier?
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- mechanisms that contribute to the protection of the gastric mucosa - include: an impermeable epithelial cell surface covering, mechanisms for the selective transport of hydrogen and bicarbonate ions, and chacteristics of the gastric mucus
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Which cells in the stomach secrete hydrochloric acid?
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parietal cells of the stomach
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What are the 2 major causes of gastric irritation and ulcer formation?
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NSAIDs and infection with H. Pylori
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What is acute gastritis?
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refers to a transient inflammation of the gastric mucosa
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What are characteristics of chronic gastritis?
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- absence of grossly visible erosions and the presence of chronic inflammatory changes leading to atrophy of the glandular epithelium of the stomach - 3 major types: 1)H. pylori gastritis 2) autoimmune gastritis and multifocal atrophic gastritis 3) chemical gastropathy
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What are some characteristics of H. pylori gastritis?
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- a chronic inflammatory disease of the antrum and body of the stomach - can lead to gastric atrophy, peptic ulcer, associated with increased risk for gastric adenocarcinoma and low-grade B-cell gastric lymphoma - H. pylori produces enzymes and toxins that have the capacity to interfere with the local protenction of the gastric mucosa against acid, produce intense inflammation, and elicit an immune response - treatment includes combination therapy that includes two antibiotics and bismuth or a proton-pump inhibitor (PPI)
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What are some characteristics of peptic ulcer disease?
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- a group of ulcerative disorders that occur in areas of the upper GI tract that are exposed to acid-pepsin secretion - most common forms are duodenal and gastric ulcers - complications include hemorrhage, obstruction, and perforation
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What are 2 pharmacological methods for reducing gastric acid contents?
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1. antacids - neutralizes gastric acid 2. H2-receptor antagonist or proton-pump inhibitors - to decrease gastric acid production
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What are some characteristics of irritable bowel syndrome?
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- a functional GI disorder characterized by a variable combination of chronic and recurrent intestinal symptoms not explained bu structural or biochemical abnormalities - the hallmark of IBS is abdominal pain that is relieved by defecation and associated with a change in consistency or frequency of stools
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What are the 2 inflammatory bowel diseases?
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1. Crohn disease 2. ulcerative colitis
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What are characteristics of Crohn disease?
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- can affect any area of the GI tract from the mouth to the anus - sharply demarcated, granulomatous lesion that are surround by normal-appearing mucosal tissue - presence of skip lesions (lesions interspersed between normal segments of bowel) - involves all layers of the bowel (submucosal layer involvement is greatest) - surface of bowel has a "cobblestone" appearance - lead pipe or rubber hose appearance of the bowel wall
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What are some characteristics of ulcerative colitis?
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- confined to the rectum and colon - usually begins in the rectum and spreads proximally - affects the mucosal layer of the bowel causing stools to contain blood and mucus
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What are some characteristics of diverticular disease?
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- diverticulosis is a condition in which the mucosal layer of the colon herniates through the muscularis layer - diverticula develop between the longitudinal muscle bands of the haustra, in the area where the blood vessels pierce the circular muscle layer to bring blood to the mucosal layer - diverticulitis is a complication of diverticulosis in which there is inflammation and gross or microscopic perforation of the diverticulum
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What is the difference between small-volume and large-volume diarrhea?
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1. small-volume - results from an increase in the propulsive activity of the bowel 2. large-volume - results from an increase in water content of the stool
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What are some characteristics of peritonitis?
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- an inflammatory response of the serous membrane that lines the abdominal cavity and covers the visceral organs - most common causes are perforated peptic ulcer, ruptured appendix, perforated diverticulum, gangrenous bowel , pelvic inflammatory disease, and gangrenous gallbladder
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What are some characteristics of adenomatous polyps?
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- most common type of neoplasm of the intestine - arise from the mucosal epithelium - classified as tubular, villous, or tubulovillous adenomas
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