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GI 4-7

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imissyou419's version from 2017-04-06 20:51

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Question Answer
Large intestineinhabited by beneficial bacteria
Appendixstore bacteria that you are used to, repopulate quickly the large intestine
Haustracircular outpouching, chyme moves from haustra to haustra, help mix content of large intestine and allow for water reabsorption
Ileocecal valveclosure from small intestine to stomach (large intestine full of bacteria and small intestine low in bacteria), point where you vomit from
Large intestine motilitygastroileal reflex, haustral churning, peristalsis & mass peristalsis
Gastroileal reflexenteric NS control, presence of food in the stomach stimulates the opening of the ileocecal valve (ensures whatever left in small intestine moved to large intestine)
Haustral churningMixing of large intestine contents from 1 haustra to next (allow for bacteria to process + water reabsorption)
Peristalsis & Mass Peristalsisunidirectional movement of lumen contents out of the large intestine
Gastrocolonic reflexbabies have this, when food get to their stomach they have the urge to eliminate whatever is in their intestines
Function of bacteria in the large intestine1. fermentation of undigested carbohydrates (bacteria salvage nutrients -> anaerobic so go through fermentation which produce gas like hydrogen, carbon dioxide, methane; bacteria can partially digest cellulose/fiber),
2. digestion of remaining peptides,
3. decomposition of bilirubin (metabolite from heme in RBC),
4. production of B vitamins and vitamin K (rely on bacteria to get enough of this)
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Question Answer
Exocrine secretions from the pancreas is secreted intoduodenum through the pancreatic duct
Pancreatic acinar cellsmake proenzymes
Pancreatic ductal cellssecrete bicarb and water (to help with acidic chyme in small intestine)
Bicarbonatefrom ductal cells
Pancreatic amylaseonce it gets to small intestine, activated in neutral pH
Trypsinogen -> trypsindigest proteins
Chymotrypsinogen -> chymotrypsindigest proteins
Procarboxypeptidase -> carboxypeptidasedigest proteins, cut a.a. from carboxy terminus
Proelastase -> elastasedigest protein fibers (found in animal proteins)
Pancreatic lipasefunctions better than other lipase (gets help from colipase and bile), digest fats, correct environment is in neutral pH
Ribonucleasedigest RNA
Deoxyribonucleasedigest DNA
How are proenzymes from the pancreas made into their active form?Enterokinase (brush border enzyme) in small intestine cleaves trypsinogen -> trypsin
Trypsin cleaves chymotrypsinogen, procarboxypeptidase, proelastase into their active forms
(body does this so pancreas does not digest itself; pancreatitis - blockage of pancreatic duct and/or inappropriate activation of proenzymes in pancreas)
Acinar cell secretions from the pancreas arehomogeneous, every duct makes same composition (salivary gland produce heterogeneous solution - glands produce different solutions)
What happens to your pancreatic secretions when you stop eating meat?body makes less proelastin - ratio of zymogens and digestive enzymes will change with changing diets but acini will secrete the same composition
Cholecystokinin (CCK) from CCK cells in small intestines actionstimulate acinar secretion (increase pancreatic enzymes)
Secretin from S cells in small intestines actionstimulate ductal secretion (more bicarb and water)
Cystic Fibrosis and pancreatic insufficiencymodifications to secretions of acinar cells of pancreas are due to transporters in the ductal cells
water and bicarb is secreted into the lumen of the duct, bicarb is secreted in exchange for chloride
a chloride leak channel mintains the activity of the ^ exchanger
a mutation to this chloride channel cause cystic fibrosis
not getting enough bicarb and water secretion in pancreas duct result in more viscosity of enzymes from acinar cells, less volume (incl. enzymes) get into small intestine -> malnutrition
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Question Answer
Bile solution is made byliver
How is bile transported to the gallbladder?through hepatic duct, cystic duct
Gallbladderbile solution concentrated and stored until it is stimulated for release (more concentrated -> more effective @ lipid digestion, bile is detergent)
Sphincter of Oddiclosure of common bile duct to duodenum (for common bile duct & pancreatic duct)
Hepatic arteryliver receives oxygen rich blood from hepatic artery
Hepatic portal veinvenules collect from stomach, small intestine, large intestine nutrient-rich, deoxygenated blood into hepatic portal vein to liver
In liver processingmixing of oxygen rich (hepatic artery) and nutrient rich (hepatic portal vein) blood, process the contents of the blood and determine what needs to go to rest of the body via hepatic vein, returning to regular circulation
Triadon each of 6 corners;
Portal arteriole - originally hepatic artery;
Portal venule - originally hepatic portal vein, drain into central vein then hepatic vein;
Bile duct - hepatocytes secrete bile into bile canaliculi go into bile duct, destined to go to duodenum
How are hepatocytes organized?in plates called hepatic laminae, exposed to sinusoid contents & bile canaliculi
Hepatocyte functionblood contents processed (hepatocytes are full of enzymes to modify food they absorb), nutrients from GI tract metabolized (convert monosaccharides from diet into glucose in sinusoids)
Liver functions1. Synthesis of bile salts/acids - component of bile (lipid digestion)
2. Detoxification & elimination of xenobiotics and endogenous metabolites (make toxic things safe, endogenous metabolite bilirubin get eliminated through bile)
3. Metabolism of carbohydrates, lipids and proteins (liver first goes to lymphatics, carbohydrates & protein first go to liver to be processed)
4. Synthesis of essential proteins - albumin, clotting factors
5. Immune function - resident macrophages
BileComplex solution containing bile acids, phospholipids, cholesterol, water, ions made by hepatocytes (along with ductal cells of bile duct secreting water and bicarb into bile solution -> increase volume & provide neutralization when it gets to duodenum)
+ waste products (hydrophobic substances) destined for excretion
Bile acids made fromcholesterol in the liver, function to solubilize lipids from the diet to permit for optimal chemical digestion (detergent)
Cholecystectomycholesterol based stones likely due to an imbalance of liver production of cholesterol and other lipids (hypersecretion of cholesterol into bile canaliculis), episodic pain can occur (following high fat meal) and if frequent, cholecystectomy is required; consequences: can't concentrate their bile, eat less fat, constant secretion of bile from liver can be upregulated
Jaundiceyellow pigment because of increased unconjugated or conjugated bilirubin that deposit in their skin from their blood, hepatocytes could not put conjugated bilirubin into bile cannalicus or blockage of common bile duct, common hepatic duct by gallstones or nonconjugated (too many RBC being broken down); babies get jaundice because their ducts aren't formed -> massive turnover of haemoglobin, treat with phototherapy
Bilirubin metabolizing processbreakdown product from haemoglobin, cells of spleen and Kupffer cells can convert haeme to biliverdin then to bilirubin, bilirubin is bound to albumin to make it soluble and transported through the blood, hepatocytes absorb and modify (conjugate) bilirubin so it can be secreted into bile ducts
Bile acid production, secretioncontrolled by how much bile acid return to liver (via hepatic portal vein), neural and hormonal (most important) inputs regulate bile production, secretion, and release from gallbladder - CCK
Which part of the small intestine reabsorb bile?ileum for recycling, bile release increases as digestion and absorption occurs
What part of bile solution are absorbed?water, ions leaving behind bile salts, cholesterol, bilirubin
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