Term
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Definition
-both exocrine and endocrine -exocrine = production and release of digestive enzymes -digestive hormones produced in aggegates of cells called: ISLETS OF LANGERHANS -eventually released into bloodstream
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Term
Exocrine component of Pancrease 6 enzymes |
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Definition
1. lipase = breaks down fats 2. carboxypeptidase = breaks down peptide bonds 3. trypsin = hydrolyzes peptide bonds 4. chymotrypsin = cleaves carboxyl links of AA 5. amylase = breaks down startch and glycogen 6. elastase = hydrolyzes elastin |
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Term
| Pancreatic Secretion of Exocrine Component |
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Definition
-controlled by 2 hormones and a neurotrasmitter -hormones are synthesized by enteroendocrine cells -in duodenum Hormones: -secretin -cholecystokinin Neurotransmitter: -acetylcholine
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Term
Secretin in Pancreas (Exocrine) |
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Definition
-produced by enteroendocrine cells of small intestine -causes buffer to be released by ductal cell -insulin release |
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Term
Cholecystokinin in Pancreas (Exocrine) |
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Definition
-produced by APUD cells of small intestine -causes gall bladder contraction -slows gastric emptying time -stimulates pancreas enzyme secretion |
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Term
Acetylcholine in Pancreas (Exocrine) |
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Definition
-released from postganglionic parasympathetic fibers
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Term
| Exocrine Structure of Pancreas |
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Definition
-compound acinar gland (similar to parotid) -acini made of: -acinar -centroacinar cells -(intra-acinar extension of intercalated ducts) -NO striated ducts -intercalated ducts merge into columnar interlobular ducts -Interlobular ducts lead to 2 main ducts of pancreas 1. duct of Santorini (accessory but really main) 2. duct of Wirsung (main) |
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Term
| Interlobular ducts lead to 2 main ducts of pancreas
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Definition
| 1. duct of Santorini (accessory but really main) 2. duct of Wirsung (main) -duct cells produce bicarbonate-rich buffer solution which neutralizes the acidic gastric contents going into duodenum |
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Term
| Endocrine Component of Pancreas |
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Definition
-consists of ISLETS OF LANGERHANS -islets distributed throughout pancreas BUT -more numerous in the tail of gland
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Term
Structure of Endocrine Pancreas (Islets of Langerhans) |
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Definition
-round to polygonal in shape -surrounded by rich capillary network -thin capsule of reticulin fibers seperae each islet from exocrine pancreatic parenchyma |
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Term
| 5 types of cells comprise the islets |
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Definition
1. α (A) cells 2. β (B) cells 3. δ (D) cells 4. F (PP) cells 5. G cells
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Term
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Definition
-large cells with dark cytoplasm -found on periphery of islet -constitute 20% of islet cells -secrete glucagon (increase blood sugar) |
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Term
Glucagon from α (A) cells
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Definition
-released when blood glucose levels are low -acts on hepatocytes -breaks down glycogen into glucose -releases it into bloodstream -activates gluconeogenesis
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Term
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Definition
-comprise 70% of islet -smaller in cell and granule size than α cell -secrete insulin (decreases blood sugar) |
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Term
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Definition
-binds to insulin receptors on cell (especially skeletal muscle, liver and adipose) -allows glucose to be taken into cell -encourages glucose utilization by cells -increases protein synthesis -formation and storage of neutral lipids |
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Term
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Definition
-5% of islets cells -secrete somatostatin |
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Term
| Somatostatin in δ (D) Cells |
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Definition
-both paracrine and endocrine function Paracrine = inhibit hormone release in adjacent α and β cells of pancrease Endocrine = reduces smooth muscle contractions of alimentary tract and gall bladder
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Term
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Definition
- 1% of islet -secrete pancreatic polypeptide -inhibits exocrine pancreatic secretions |
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Term
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Definition
- 1% of islet cells -secrete gastrin -stimulate production of HCl by parietal cells in stomach |
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Term
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Definition
-2nd largest organ -processes and stores the nutrients absorbed by digestive tract |
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Term
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Definition
-surrounded by a thin capsule (Glisson's capsule) Capsule extends into orgad subdividing it into lobes and lobules |
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Term
Majr Divisions of Liver (3) |
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Definition
1. Liver Lobule 2. Portal Lobule 3. Hepatic Acinus |
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Term
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Definition
-classic lobule -poorly-demarcated hepatocytes form hexogonal struc -contains portal triad =point where 3 lobules contact each other -center of lobule has central vein -has converging plates of anastomosing hepatocytes enclosing sinusoids
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Term
| Portal Triad of Liver Lobule |
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Definition
=point where 3 lobules contact each other Contains: -connective tissue -branches of hepatic artery -portal vein -bile duct -sometimes lymphatics |
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Term
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Definition
-bile drainage -triangular structure -portal triad at the center -central vein at the tip of each angle |
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Term
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Definition
-diamond shaped -supplied by terminal branch of distributing veins -from protions of 2 adjacent liver lobules -divided into zones based on proximity to distributing veins zone I zone II zone III |
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Term
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Definition
-closest to distributing vein -first to affect or be affected by the passing blood -actively synthesizing proteins |
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Term
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Definition
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Term
| Hepatic Acinus - Zone III |
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Definition
-encountes blood on its way to central vein =blood has been altered by zones I and II -largely deoxigenated blood -hepatocytes play a role in detoxification
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Term
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Definition
-recieves blood from 2 sources 1. portal vein 2. hepatic artery
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Term
| Liver Blood Supply from Portal Vein |
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Definition
-80% blood supply -oxygen poor -nutrient rich -from pancreas, spleen, and intestines |
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Term
Liver Blood Supply from Portal Vein (the flow) |
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Definition
-in triads: branches of portal vein called: portal venules -branches that surround periphery of lobues called: distributing veins -distributing veins have inlet venules emerging which lead to sinusoids -sinusoids lead to central vein -central vein merges with sublobular vein at base of lobule -sublobular vein joins with other sublobular vains to form hepatic veins
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Term
| Liver Blood Supply from Hepatic Artery |
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Definition
- 20% blood - oxygen rich - branches to form interlobular arteries - some occupy portal area - some empty directly into sinusoids |
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Term
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Definition
| Contain BOTH arterial and venous blood!!! |
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Term
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Definition
-polyhedral cells -1-2 nuclei form anastomosing plates -converge towards central vein -exposed at several points to walls of sinusoids or adjacent hepatocytes *space between adjacent hepatocytes is called: Bile Canaliculus
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Term
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Definition
1. Storage - vitamins (mostly A,D,B12) 2. Transformation and Detoxification - inactivation on drugs and toxins 3. Protein Synthesis - mainly blood proteins (for coagulation, immune system, transport) 4. Metabolism - lipids, carbohydrates, proteins 5. Excretion - bilirubin (breakdown products of hemoglonin) 6. Bile Production - absorbs fats, eliminates most of the cholesterol produced by liver, excretes the breakdown products of blood |
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Term
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Definition
Space of Disse: seperate endothelial cells of the sinusoids from the hepatocytes Contains: -hepatocyte microvilli -nonmyelinated nerve fibers -Ito cells (fat storage) -pit cells (type of NK cell) phagovytic Kupffer cells - reside within sinusoids (macrophages) |
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Term
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Definition
Composed of: -cholesterol -lecithin -fatty acids -bilirubin glucuronide -bile salts -water -most of the componets are absorped in intestine and transported via blood to bile canaliculi |
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Term
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Definition
-initial part of bile duct system -consist of narrow channels b/w adjacent hepatocytes -microvilli protrude into the spaces b/w hepatocyes -reach endpoint near portal areas =bile flows in opposite direction of blood -at periphery of liver lobule, bile moves in bile ductules (clear cuboidal cells), then continues to bile ducts of portal triad -numerous bile ducts converge to form right and left hepatic ducts |
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Term
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Definition
-hollow organ -rests along underside of liver
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Term
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Definition
-bile storage -bile concentration -bile release |
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Term
| Gall Bladder Communication |
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Definition
| Communicates with hepatic duct via cystic duct to form common bile duct |
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Term
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Definition
-highly folded -simple columnar epithelium -lamina propria composed of: -areolar connective tissue -discontinuous muscularis externa -serosa -NO muscularis mucosa |
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Term
| Gall Bladder and Tubuloacinar Galnds |
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Definition
-tubuloacinar glands near cystic duct -produce and release mucose into bile |
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Term
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Definition
-produced with cholecystokinin -CCK released by enteroendocrine cells of small intestine -CCK stimulated by dietary fat present within lumen
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Term
ampulla of Vater (Gall Bladder) |
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Definition
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Term
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Definition
-surrounds junction of common bile duct and pancreatic duct -smooth muscle -governs amount of bile being pushed through |
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Term
Rokitansky-Aschoff Sinuses (Gall Bladder) |
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Definition
-technically don't exist -just an extension of the lumen (a recesses / inpocketing) -communicates with lumen |
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