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88 Cards in this Set
- Front
- Back
what marks the entry of the small intestine into the peritoneal cavity?
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jejunum
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what does the superior mesenteric artery supply?
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proximal jejunum to hepatic flexure
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what does the inferior mesenteric artery supply?
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hepatic flexure to the rectum
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what supplies the lower portion of the rectum?
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hemorrhoidal branch of internal iliac or pudendal
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where are the stem cells of the small intestine located?
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crypts of Lieberkuhn
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where are Brunner's glands and what is there function?
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duodenum and secretion of bicar., glycoproteins, and pepsinogen II
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where are secretary granules released from endocrine cells in the gut?
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at or near the basal surface
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function of M cells?
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move antigenic macromolecules from the lumen to under the surface epithelium
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function of plasma cells?
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secrete IgA,IgG,IgM
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where is Meissner's plexus located?
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base of the submucosa
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where is Auerbach's plexus located?
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between the muscle layers of the muscle wall
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atresia
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complete closure of an opening
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defect in Meckel diverticulum?
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failure of involution of the vitelline duct (connects lumen of developing gut to the yolk sac), creates a blind pouch on the mesenteric side of the bowel
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defect in Hirschsprung disease?
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intestinal segment with missing ganglion cells (Meissner and Aurbach plexi)
obstruction and dilation proximal to defect |
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mutation causing Hirschsprung disease?
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RET gene inactivating the kinase activity
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hallmark of malabsorption disease?
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steatorrhea
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defect in Celiac's disease?
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mucosal lesion of the small intestine and impaired nutrient absorption-T cell mediated inflammation due to intolerance to gluten
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what is necrotizing enterocolitis?
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acute, necrotizing inflammation of the intestines with necrosis of intestinal segments
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what do neonates with necrotizing enterocolitis present with?
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bloody stool, distended abdomen and gas in the intestinal wall
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dysentery
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low-volume, painful, bloody diarrhea
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what does rotavirus do?
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selectively destroys mature enterocytes in the small intestine-replaced by secretory cells
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where are antirotavirus antibodies located?
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mother's milk
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morphology of viral gastroenteritis?
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shortened villi, lymphocytes in the lamina propria, loss of brush border, hypertrophied crypts
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another name for bacterial enterocolitis?
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food poisoning
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main property of bacteria contributing to the pathogenesis of enterocolitis?
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ability to adhere to mucosal epithelial cells by plasmid-encoded adhesins
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what do staph enterotoxins do?
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proteins that bind to Ag receptors of T cells and stimulate cytokine secretion- intestinal motility and fluid secretion
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what does the cholera enterotoxin do?
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increases intracellular Ca, dysfunction of the fluid and electrolyte transport
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what does shigella do?
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invades intestinal mucosal cells and destroys them causing hemorrhaging
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what does salmonella do?
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invades intestinal epithelial cells and macro's, secretion increased by neural reflex pathways
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what characterizes pseudomembranous/antibiotic colitis?
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adherent layer of inflammatory cells and debris overlying sites of mucosal injury
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what causes antibiotic colitis?
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C. difficile
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characteristics of most bacterial infections of the GI?
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epithelial damage, decreased maturation, increased mitotic rate, hyperemia and edema of the lamina propria
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where does shigella primarily affect?
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distal colon
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where does salmonella primarily affect?
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ileum and colon
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what is the most common pathogenic parasitic infection in humans?
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giardia-protazoan
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what is important in resistance to giardia?
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Ab mediated immunity
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how does giardia work?
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trophozites adhere to but do not invade epithelial cells-diarrhea not dysentery
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what is primarily affected by T. whippelii?
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intestines, CNS and joints
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what does T. whippelii invade?
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macrophages without an immune reaction
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hallmark of Whipple disease?
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small-intestinal mucosa with distended macrophages in the lamina propria
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name the types of IBD
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ulcerative colitis
crohn's |
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pathogenic abnormalities in IBD?
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immune response against intestinal flora
defect in epithelial barrier genetic susceptibility |
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GI affected by Crohn's?
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any part
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presentation of Crohn's?
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abdominal pain, anemia, mild diarrhea, fever
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fistula
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abnormal communication between organs
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gross features of Crohn's?
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discontinuous
thickened wall with stricture and fissures fistulas and perforations cobblestoning of the mucosa creeping fat |
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microscopic features of Crohn's?
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patchy inflammation
aphthous-shallow ulcers above lymph nodules cryptitis occasional granulomas |
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presentation of ulcerative colitis?
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recurring bloody mucoid diarrhea
waxes and wanes |
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what is preventative of UC?
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smoking
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gross features of UC?
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continuous disease starting in the rectum and moving proximally
only colon no thickening inflammatory pseudopolyps occasion megacolong |
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microscopic features of UC?
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diffuse mucosal inflammation
cryptitis little ulceration polyps risk of colon carcinoma |
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the two diseases requiring prophylactic colectomy?
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UC and FAP
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extraintestinal manifestations of IBD?
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liver-primary sclerosing cholangitis
polyarthritis uveitis-eye skin pulmonary inflammatory fibrosis |
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three levels of severity in GI vascular disorders?
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mucosal infarction
mural infarction transmural infarction |
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is the superior or inferior mesenteric artery more affected by ischemia?
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inferior
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two phases of injury in ischemic bowel disease?
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initial hypoxic injury
secondary re-perfusion injury |
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major causes of vascular obstruction?
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arterial/venous thrombosis
arterial embolism nonocclusive ischemia physical |
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uveitis?
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inflammation of the uveal tract, behind the cornea
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diverticulum?
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outpouching or invagination of the mucosa into the wall of the bowel
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true diverticuli?
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includes the mucosa plus the entire wall
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pseudodiverticuli?
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only the mucosa
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cause of diverticular disease?
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increased intraluminal pressure, weakness in the wall
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where is the most common site of diverticulum?
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left colon
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common types of intestinal obstruction?
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hernia
adhesions volvulus intussusception |
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volvulus
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contortion of a loop of intestine causing obstruction
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intussusception?
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enfolding of one part of the intestine into another
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what is a hyperplastic polyp?
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small, single polyp with no dysplasia
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what is a Peutz-Jeghers polyp?
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tumor-like growth
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most common location for small intestine tumors?
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duodenal ampulla
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what disease is associated with small intestine tumors?
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FAP
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what increases the chances of cancer in an polyp?
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high number
increased size sessile- less stalk high grade dysplasia |
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defect in FAP?
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autosomal dominant germline mutation of APC gene
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presentation of FAP?
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hundreds of colonic polyps
other tumors and lesions |
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association of FAP and cancer?
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100%
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defect in HNPCC
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autosomal dominant mutations in DNA repair genes
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where are HNPCC polyps more likely to appear?
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right side of colon
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two pathways of colorectal carcinogenesis?
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APC gene pathway
MMR gene pathway |
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mechanism in APC gene pathway to colon cancer?
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most are somatic mutations
at least seven mutations leading to metastasis |
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what pathway occurs in FAP?
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ACP gene pathway
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what pathway occurs in most of HNPCC?
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MMR gene pathway
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mechanism in MMR gene pathway to colon cancer?
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mutation in any DNA repair of MMR genes- produces DNA fragments or microsatellites
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presentation in right-sided colon cancer?
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slow blood loss leading to anemia, weakness
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presentation in left-sided colon tumors?
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altered bowel function, bleeding
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location of most tumors in colorectal carcinoma?
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left side
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gross presentation of carcinoid tumor?
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ball in the wall of the intestines protruding into the lumen with a dimple
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which has the better prognosis: carcinoid or carcinoma?
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carcinoid
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is prognosis of B or T cell GI lymphoma better?
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B
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mechanism of acute appendicitis?
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obstruction by lymphoid,hyperplasia,tumor or fecal stone
elevated WBC's risk of perforation, abscess and peritonitis(inflammation) |