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38 Cards in this Set
- Front
- Back
List the 4 general layer of the GI tract |
- mucosa - submucosa - muscularis propria - serosa or adventitia |
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Which layers of the GI tract contain plexuses and what are the called? |
- submucosa: submucosal plexus - muscularis propria: myenteric plexus |
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List the 3 layers of the mucosa |
- epithelium - lamina propria - muscularis mucosa |
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What are the 2 types of muscle found in the GI tract and what are their general function |
- circular smooth muscle: contraction causes constriction - longitudinal smooth muscle: contraction causes shortening |
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Which cranial nerves innervate the mouth |
CNs VII and IX |
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Name the three salivary glands in the mouth |
- parotid - submandibular - sublingual |
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In the mouth, what is the function of; a) mucous b) amylase c) bicarbonate d) thiocynate and lysosymes |
a) lubrication b) digest starches c) neutralise acid d) bacteriocidal agents |
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Name two disease of the heart associated with dental carries |
- endocarditits - Ludwig's angina |
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What are are the functions of mastication (3) |
- reduce particle size in the food bolus - mix food with saliva (lubrication and enzymes) - increase surface area |
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Where is the "swallowing centre" |
reticular formation of the brain stem |
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What is the function of the oesophagus (1) |
- the conduit which propels the bolus from the pharynx to the stomach |
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Which nerve innervates the oesophagus and which layer? What is the response of parasympathetic and sympathetic stimulation? |
- vagus (CN X); muscularis - parasympathetic increases peristalsis (and vice versa) |
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Which arteries supply the oesophagus (8) |
- superior and inferior thyroid arteries - branches of the bronchial, intercostal and descending aorta arteries - branches of left gastric, left inferior phrenic and splenic arteries |
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Why is infarction in the oesophagus rare? |
- dense anastomosis in the submucosa |
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What is the function of the stomach (3)? |
- food reservoir - initiates digestion - controlled release of contents into the duodenum |
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What components make up gastric secretions (5)? |
- intrinsic factor - H+ ions (produced by parietal cells) - pepsin (formed from pepsinogen released from chief cells) - mucous - water |
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What is the function of stomach acid (2)? |
- activate pepsin from pepsinogen - kill bacteria |
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What are the 3 phases of gastic secretion and, if applicable, what is their stimuli? |
- cephalic (sight/smell/taste of food) - gastric (food entering stomach or duodenum) - intestinal |
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What happens in the cephalic phase (3)? |
- stimulus: sight/smell/taste of food - stimulation of vagus nerve - moderate stimulation of HCl and pepsingogen |
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What happens in the gastric phase (3)? |
- distension of stomach and proteins entering the antrum - activation of vago-vagal reflex and release of gastrin (and histamine) - strong stimulation of HCl and pepsinogen |
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In the intestinal phase, what is the response of proteins, HCl and lipids in the duodenum |
proteins: > gastrin (excitatory) HCl: > secretin (inhibitory) lipids: > peptide YY (inhibitory) |
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List 3 anatomical factors in the jejunum/ileum which increase surface area |
- Kerckring's folds - villi - microvilli |
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Where are Brunner's glands found and what is their function? |
- duodenum in submucosa - secrete alkaline bicarbonate |
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Where are Peyer's patches found? |
- ileum |
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What are the three function of the small intestine? |
-mix food with digestive secretions and enzymes - circulate contents to allow contact with mucosa - propel contents towards the terminal ileum |
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What are the 4 types of movement which propel food through the small intestine |
- segmentations of circular smooth muscle - pendular contractions of longitudinal muscle - villus movements - peristaltic waves |
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What is produced by the crypts of LieberKuhn in the small intestine and what is their function (3/3)? |
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What is produced by villus tips in the small intestine and what is their function (1/1)? |
- brush border enzymes - digestion |
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Which macromolecules undergo digestion in the stomach and what enzymes (activated and inactivated) perform the digestion? |
- proteins - pepsin converted from pepsinogen |
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Which substances undergo digestion/absorption in the small intestine and what enzymes (activated and inactivated) perform the digestion? |
- protein (trypsin and other proteases) - lipids (bile salts perform emulsification and lipases become activated) - carbs (amylase/maltase/sucrase/lactase) - vitamins (passive diffusion; B12 is absorbed in the ileum and requires intrinsic factor) - water (absorbed from the ileum (7-8 litres) by diffusion) |
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- where are acinar cells found? - what do they produce? - what stimulates secretion of their products |
- pancreas - pro-enzymes (zymogens) for digestion and Na Cl - proteins and lipids stimulate the production of cholecystokinin which stimulates the release of zymogens |
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- where are duct cells found? - what do they produce? what stimulates secretion of their products? |
- pancreas - bicarbonate - HCl in the duodenum stimulates the production of secretin which stimulates the release of bicarbonate from the duct cells |