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46 Cards in this Set
- Front
- Back
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Lingual Papillae
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Any of the tiny eminences on the final back 2/3rds of the tongue.
Circumvalate - 8-12 large, dome-like structures. Moat-like invagination lined with strat squam epithelium containing numerous taste buds. Washed by lingual salivary (von Ebner's) glands to empty their contents. Fungiform - Mushroom shaped, scattered but projecting above the filiform papillae. Strat squam epithelium with taste buds on dorsal surface. Filiform- Smallest but most numerous in humans. In cats, these are responsible for the rough tongues. This strat squam, highly keratinized epithelium does not contain taste buds, serving to move food around. Foliate - Parallel low ridges seperated by deep mucosal clefts. Found in the young with many taste buds and small serous glands. |
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What is the texture of a taste bud?
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Explain the general organization of the alimentary canal.
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<img src="canal.png" />
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Describe the structure and function of the esophagus.
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25 cm long
Narrowest part of alimentary path Most muscular segment of GI tract Lumen normally collapsed by tonus of muscularisexterna, throwing mucosa into longitudinal folds Conforms to “typical”4-layered alimentary tube structure |
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Describe the structural organizaton of the tunics of the stomach.
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<img src="pasteimqqux.png" />
1. Mucosa a. epithelium b. lamina propria c. muscularis mucosa 2. Submucosa a. submucosal (Meissner’s) plexus b. submucosal glands (oesophagus & duodenum) 3. Muscularis externa a. inner layer ‑ circular b. outer layer ‑ longitudinal c. myenteric (Auerbach’s) plexus 4. Adventitia or serosa |
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Name and describe the glands of the gastric mucosa.
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<img src="gastricglands.png" />
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Name and describe the types of cells in the gastric mucosa.
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<img src="gastriccells.png" />
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Name the different parts of the small intestine.
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Three segments:–DUODENUM-25 cm long
–JEJENUM-2.5 m long –ILEUM-3.5 m long |
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Describe the glands of the gastric mucosa - cardiac glands.
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•Limited to narrow region of stomach
–near esophageal orifice •Secretion, along with that of esophageal cardiac glands –contributes to gastric juice •tubular glands •tortuous •sometimes branched •composed of mucous secreting cells –short duct segment •connects gland with shallow gastric pits •some enteroendocrinecells interspersed <img src="pasten4bcmi.jpg" /> |
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Name and describe the glands of the gastric mucosa - fundic glands.
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Fundicglands; also called gastric glands
•Produce digestive juice of stomach •Present throughout gastric mucosa –except where cardiac and pyloric glands occur •Simple branched tubular glands •Extend from bottom of GASTRIC PITS to muscularismucosae •Gastric pits shorter-glands longer •Several glands open into one gastric pit •Each gland has –narrow, long NECK SEGMENT –short wide BASE or FUNDIC SEGMENT •Base divides into 2 or 3 branches –may be coiled near muscularismucosae Composed of 4 functional cell types: –MUCOUS NECK CELLS –CHIEF CELLS –PARIETAL CELLS (Oxyntic Cells) –ENTEROENDOCRINE CELLS –UNDIFFERENTIATED CELLS <img src="pastexxrfhh.jpg" /> <img src="paste8dlu29.jpg" /> |
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Name and describe the glands of the gastric mucosa - pyloric glands.
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Composed of 4 functional cell types:
–MUCOUS NECK CELLS –CHIEF CELLS –PARIETAL CELLS (Oxyntic Cells) –ENTEROENDOCRINE CELLS –UNDIFFERENTIATED CELLS <img src="paste8bpu9a.jpg" /> |
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Name and describe the glands of the gastric mucosa - mucous neck cells.
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•Located in neck region
•Shorter than surface mucous cell –do not exhibit prominent mucous cap –Nucleus tends to be spherical rather than elongate –as in surface cells •Secretes a soluble mucous –compared to viscous surface mucous <img src="pastelec7dq.jpg" /> |
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Name and describe the glands of the gastric mucosa - parietal oxyntic cells
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•Called OXYNTIC CELLS
•Secrete HCl –and intrinsic factor •Located in neck –among mucous neck cells •Most numerous in upper and middle sections •Give glandular epithelium beaded appearance. •Large cells –often binucleate, •Appear triangular –with apex directed toward lumen of gland •EM shows extensive INTRACELLULAR CANALICULAR SYSTEM –communicates with lumen of fundicgland –Numerous surface microvilliproject from canaliculi •HClproduced in the lumen of the intracellular caniculi <img src="pasteqkhfva.jpg" /> <img src="pasteokdwmv.jpg" /> |
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Name and describe the glands of the gastric mucosa - chief cells
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•Typical protein-secreting cells
•Loactedin the deepest part of fundicglands •Cuboidalor low columnar •Cells easily identified by intense basophilia –Basal RER and apical granules responsible for basophiliaand acidophilia •Secrete: –pepsinogen –a weak lipase <img src="pasteqkhfva.jpg" /> |
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Name and describe the glands of the gastric mucosa - enteroendocrines.
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•Located at any level of gland
•small cells •sit on basal lamina •Cells hard to identify –but clear cytoplasm stands out in contrast to chief cells •EM shows small, membrane-limited granules. •Produce gastrin, secretin,cholecystokinin •Secrete products into lamina propria. <img src="pasteeeqabs.jpg" /> <img src="pastexzs1l4.jpg" /> |
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Name the structure and function of villus.
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•Epithelium--simple columnar
•Finger-like; leaf-like projections •Core of villusconsists of –extension of lamina propria –network of fenestrated capillaries beneath •Lamina propriacontains blind ended lymphatic capillary –CENTRAL LACTEAL •Smooth muscle accompanies lacteal <img src="pastewvqaig.jpg" /> |
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Name the structure and function of microvilli.
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•MICROVILLI
–of enterocytes •are major amplification of luminal surface. •Each cell has several thousand •In LM give apical region of cell a striated appearance (or BRUSH) •Each microvillus –has core of actinmicrofilaments •that are anchored to plasmalemmaat tip •extend into apical cytoplasm to insert into TERMINAL WEB <img src="pastepog5pg.jpg" /> |
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Name the structure and function of Valves of Kerckring.
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PLICAE CIRCULARES
–valves of Kercking »permanent transverse folds that contain a core of submucosa »Each fold circularly arranged »extends around half to 2/3 of circumfere <img src="pastelixybq.jpg" /> <img src="paste2njm9k.jpg" /> |
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Name the different types of cells found in the intestinal glands and describe their secretion, structure and location.
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Intestinal glands
•CRYPTS of LIEBERKUHN –Extends from Villous base to muscularismucosae –Lined by single layer of epithelial cells –Constantly renewed –Cells slough into lumen •Lamina propria surrounds glands •Lamina propria also contains –lymphatic nodules •important part of GALT •Nodules are especially large in ileum –called PEYER’S PATCHES <img src="pastewvqaig.jpg" /> |
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Describe the transport mechanism in the absorption of lipids, carbohydrates, proteins, water and electrolytes.
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•Carbohydrates
-absorbed as monosaccharides -pass through enterocyteinto capillaries •Proteins -absorbed as amino acids & peptides -pass through enterocyteinto capillaries Lipids •Hydrolysis of lipids to monoglyceride •Cross microvillimembrane and resynthesizedto triglycerides in smooth endoplasmic reticulum •Triglyceride covered by a thin layer of protein-chylomicron •Chylomicronscross the lateral membrane by exocytosis–enter intercellular spaces •Pass through basal lamina into lacteal Water and electrolytes Secreted by crypt cell activity Assist the process of absorbtionand digestion Absorbed by villuscell activity Absorption also through leaky tight junctions |
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Describe the progressive changes seen in the tunics of the small intestine and characterize the features of the duodenum.
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•Duodenum
-Distinguished by plicaecircularis -Long prominent villi(leaflike) -fewer goblet cells -presence of SUBMUCOSAL DOUDENAL GLANDS(OF BRUNNER) <img src="paste1ynsv2.jpg" /> |
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Describe the progressive changes seen in the tunics of the small intestine and characterize the features of the jejunum.
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•Jejunum
-Long prominent villi -More number of goblet cells -No submucosalglands <img src="paste8mxgyo.jpg" /> |
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Describe the progressive changes seen in the tunics of the small intestine and characterize the features of the ileum.
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•Ileum
-Short villi -Goblet cells increase -Presence of large aggregates of lymph nodules:Peyer’spatches(GALT) -Peyerspatches –appear dome shaped when viewed from luminal surface -Epithelium covering peyerspatches –M cells <img src="pastez7pvm2.jpg" /> |
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Describe the tunics of the large intestine - mucosa
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Mucosa
•Contains numerous CRYPTS OF LIEBERKUHN •Simple columnar epithelium –Absorptive cells look like those of small intestine –primary function of ABSORPTIVE CELLS •absorb water and electrolytes •Goblet Cells –Secrete much mucous -Facilitates elimination of waste material •Undifferentiated cells •No Panethcells(excappendix) <img src="pastetqdtjs.jpg" /> |
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Describe the tunics of the large intestine - muscularis
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•Outer layer
–partly formed into dense bands called TENIAE COLI -teniae pucker wall between into haustrae. <img src="pasteuetz8m.jpg" /> |
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Describe the structure of the appendix.
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•APPENDIX is a thin finger-like extension of the CECUM.
–Appendix is different in that it has a complete layer of longitudinal muscle in the muscularis •Conspicuously, large numbers of lymphatic nodules –located in wall of appendix •also trash in lumen <img src="paste36krbt.jpg" /> |
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Describe the structure and function of the rectum and anal canal.
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•No teniae
•Rectum is dilated –Upper part notable by presence of TRANSVERSE RECTAL FOLDS •Anal canal Upper part has longitudinal folds called ANAL COLUMNS Depressions between anal columns called ANAL SINUSES Mucosa like rest of colon - distal anal canal lined with stratified squamous epithelium continuous with that of skin Submucosa has terminal branches of superior rectal artery and rectal venous plexuses –Enlargements of submucosal veins are INTERNAL HEMORRHOIDS <img src="pastexqbtfh.jpg" /> <img src="pastey0dj6d.jpg" /> <img src="pasteqfzp2i.jpg" /> <img src="pastemivab6.jpg" /> |
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Compare and contrast esophago-gastric- and recto-anal junctions.
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<img src="pastevnmk4j.png" />
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Describe the changes in the autonomic nerve plexus in the wall of the GIT that may lead to Hirschsprung Disease (congenital mega colon).
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Congenital disorder of the colon where ganglion cells in the myenteric plexus, responsible for moving food, are absent.
Symptom - chronic constipation Diagnosis - barium enema or rectal biopsy. Treatment - "pull-through" surgery where the portion of the colon that does have nerve cells is pulled through and sewn over the part that lacks nerve cells <img src="paste82hmpj.png" /> |
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Describe the change in the epitheium of the lower esophagus resulting from gastro-esophageal reflux disorder (GERD) and its relationship with (Barrett's Esophugus).
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Also known as Gastroesophageal Reflux Disease (GERD)
Failure of the Lower Esophageal Sphincter (LES) at the junction of the stomach and esophagus to remain tightly closed when not passing substances INTO the stomach. Symptoms - Acid Reflux and Heartburn Prognosis - Metaplasia with eventual dysplasia as epithelium changes to columnar. Treatment - Medicine while mild, Surgery where chronic (Fundiplication) 1 in 10 patients with GERD are found to have Barrett's oesophagus some of which may lead to invasive adenocarcinoma of the esophagus (with poor prognosis) <img src="pastesh4to3.png" /><br /> |
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Explain the consequences of varicosities of the esophagus and the rectum.
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Esophagus - linked with liver cirrhosis
Rectum - referred to as piles or hemorrhoids Prognosis - danger of blood clots, deep vein inflammation or thrombophlebitis leading to pulmonary embolism and possible death. Women are twice as likely to develop varicose veins than men. |
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Describe the changes that occur in the wall of the gastro intestinal tract after surgical procedures like appedectomy, which may lead to adhesions.
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Abnormal connections to abdominal organs by thin fibrous (scar) tissue
Cause - a complication of abdominal surgery Prognosis - intestinal obstruction preventing normal flow of intestinal contents, possible hernia <img src="pasteqgvlxg.png" /> |
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Describe the changes in the villi in malabsorption syndrome.
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Coeliac sprue - autoimmune inflammatory disorder caused by intolerance to gluten (found in wheat and other grains).
Diagnosis - blood testing while diet still contains gluten, biopsy following positive result Prognosis - inflammation of the intestines, vitamin deficiencies due to lack of absorption of nutrients, and bowel abnormalities. <img src="pastehjyntj.png" /> |
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Describe the changes to the wall of the stomach in the development of ulcers. Aslo describe the effect of aspirin (NSAIDs) on the wall of stomach. Describe the main complications of chronic peptic ulceration.
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Peptic Ulcer Disease - an open sore that develops on the inside lining of the stomach (gastric ulcer), or the small intestine (duodenal ulcer).
Symptoms - burning or gnawing pain in the centre of the abdomen (stomach). Complications - Gastrointestinal bleeding when the ulcer erodes a blood vessel. Blood is a laxative and the loss of fluids can become life threatening. Perforation at the anterior surface of the stomach leads to acute peritonitis. Perforation of the gastro-intestinal wall may lead to spillage of stomach or intestinal content into the abdominal cavity with possibly catastrophic consequences. Cause - inflamation of the epithelial lining - caused by Helicobacter pylori or use of non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen. Chronic peptic ulcer (stomach) is a mucosal defect which penetrates the muscularis mucosae and muscularis propria, produced by acid-pepsin aggression. The fibrous base of the ulcer may contain vessels with thickened wall or with thrombosis. <img src="pastexo3bh8.png" /> |
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Describe the histological appearance of a adenomatous polyp of the large intestine.
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Abnormal overgrowth of tissues protruding from the mucous membrane
Prognosis - higher risk of colon cancer though most are benign. Treatment - surgery Three types - villous, tubular and tubulovillous, as per the appearance and the microscopic features. Among these three types, villous adenomas are more likely to develop into colon cancer, while tubular adenoma polyps are the least dangerous. <img src="pastevgvlsp.png" /> |
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Define the term “sialolith”
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Stone in the salivary ducts (usually submaxillary) or glands.
<img src="pastepnygee.png" /> |
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Describe the main features of pleomorphic adenoma
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Benign neoplastic tumor of the salivary glands consisting of mixed epithelial and mesenchymal cell components.
It is the most common type of salivary gland tumour and the most common tumor of the parotid gland. Also known as "Mixed tumor, salivary gland type". <img src="pastei7ppkb.png" /> |
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Compare and contrast acute gastritis vs. chronic gastritis
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Acute Gastritis - sudden inflammation of the lining of the stomach covering a broad spectrum of entities which include inflammatory changes in the gastric mucosa.
Chronic Gastritis - inflammation of the lining of the stomach that occurs gradually and persists for a prolonged time. May be caused by prolonged irritation from the use of nonsteroidal anti-inflammatory drugs (NSAIDs), infection with the bacteria Helicobacter pylori, pernicious anemia (an autoimmune disorder), degeneration of the lining of the stomach from age, or chronic bile reflux. |
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Define the term “gastric dysplasia”
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Defined as unequivocally neoplastic epithelium.
Prognosis - in the gastrointestinal tract it is considered both a carcinoma precursor and a marker of high cancer risk for the site at which it is found. Gastric dysplasia Symptoms - atypical cells, abnormal differentiation or disorganized mucosal architecture |
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List the main features of gastrointestinal carcinoid tumors
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Most common primary tumor of the small bowel and appendix accounting for more than 95% of all carcinoids and 1.5% of all gastrointestinal tumors.
Cause - Endogenous secretion of serotonin and kallikrein by the interochromaffin cells of Kulchitsky, which are considered neural crest cells situated at the base of the crypts of Lieberkühn. Symptoms - flushing, diarrhea, cardiac abnormalities with possible brochoconstriction or even heart failure. <img src="paste2ki6hr.png" /> |
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Correlate the histological features of early and late acute appendicitis with the clinical signs/symptoms observed.
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Inflammation of the appendix, classified as a medical emergency requiring removal, either by laparotomy or laparoscopy.
Prognosis - high mortality, mainly because of peritonitis and shock. Symptoms - related to disturbed function of bowels. Pain in the right iliac fossa followed by vomiting and fever Treatment - urgent surgical intervention. I have no idea what the histologic features of early and late acute appendicitis are. Surgeons take it out as soon as it becomes inflamed and want to take it out even if it spontaneously gets better to prevent recurrance. <img src="paste7uufcb.jpg" /> |
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List the main features of chronic inflammatory bowel disease and list the two major types.
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Crohn’s disease, or regional enteritis, is an inflammatory disease of the intestines that may affect any part of the gastrointestinal tract from mouth to anus, though not in a uniform manner. Affected segments are involved in their entire thickness: mucosa, submucosa, muscularis, and serosa – a transmural involvement. The ulcerated stage with mucosal loss and denudation is associated with intense inflammation and later fibrosis and contracture.
Ulcerative Colitis - acute inflammation of the mucosa with neutrophils accumulating in the lamina propia and in the lumina of the colonic glands to form crypt abscesses. Depletion of goblet cells and ulceration of the mucosa also occur. Cause - a distortion of crypt architecture, inflammation of crypts (cryptitis), frank crypt abscesses, and hemorrhage or inflammatory cells in the lamina propria. <img src="pastef1jlov.png" /> |
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Describe the main histological features and complications of diverticular disease.
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A condition which occurs when diverticula (pouches of tissue) pass through the muscular layer of the bowel, classically, the sigmoid colon. The acute condition is caused by an obstruction of fecal matter.
Complications - infection, obstruction, bleeding and perforation. Infection may lead to the formation of an abscess or even a fistula (if neighboring surfaces form an abnormal passageway) requiring surgical intervention. <img src="pasteclzdbd.png" /> |
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List the main features of adenocarcinoma of the colon
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A malignant tumor in glandular epithelium. (lit: gland tumor)
Cause - adenomas (polyps). In general, the bigger the adenoma, the more likely it is to become cancerous. For example, polyps larger than two centimeters have a 30-50% chance of being cancerous.. Research indicates that by age 50, one in four people has polyps. This is the second highest cause of cancer deaths in the US. <img src="pastetzisgw.png" /> |
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Describe the basic cause and morphological changes seen in pseudomembranous colitis.
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An infection of the large intestine from the toxin of Clostridium difficile. Normally present in the intestine, it may overgrow with antibiotics, commonly ampicillin, clindamycin, and cephalosporins.
Symptoms - the lining of the colon becomes inflamed and bleeds, and takes on a characteristic appearance called pseudomembranes. Most cases of pseudomembranous colitis happen when a person is in the hospital, because the bacteria can spread from one patient to another. Pseudomembranous colitis is rare in infants younger than 12 months old because they have protective antibodies from the mother and because the toxin does not cause disease in most infants. |
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Compare and contrast normal esophageal epithelium to that infected with Candida albicans<br />
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Caused by the fungus: Candida albicans, normally living in the mouth and the gastrointestinal tract but overgrowing when the immune system is weakened such as with HIV, diabetes, leukemia and certain cancer treating drugs.
Common locations of infection are skin, mouth, genital areas, urinary tract. <img src="pasteswaqx9.png" /> |
