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18 Cards in this Set
- Front
- Back
Describe the blood supply to the liver: also, how does it leave?
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Liver is 80% from the portal system (including nutrient-rich, o2 poor, old broken RBC's, enzymes from the intestines
Hepatic Artery = 80% this is o2 rich, nutrient poor. these merge together to form the hepatic sinusoids - so all hepatocytes receive a mixture of oxygenated/deoxygenated blood. blood leaves via the hepatic vein |
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describe a liver lobule:
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stacks of cells, generally arranged in a hexagon. each stack has between it sinusoids. at each of the 6 points, there should be portal triad (aka portal canal): a portal vein, a hepatic artery, and a bile duct.
the portal vein and hepatic artery anastamose and become the sinusoids, with blood flowing toward a CENTRAL VEIN, which drains downward into a larger vein which later becomes the hepatic vein. each lobule has 6 feeding triads. |
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do hepatocytes regenerate?
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yes! they live only about 5 months.
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describe the relationship between a hepatocyte and an adjacent sinusoid:
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a hepatocyte should have two sides facing a sinusoid for huge amount of passing blood flow.
also note that the side facing a sinusoid has the SPACE of DISSE, AKA PERI-Sinusoidal Space. It's full of microvili which increase the surface area and allow better trading of stuff. |
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what bile duct is found at triads?
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interlobar duct
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sinusoids - what kind of capillaries are they? describe. what cells do we expect to see?
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they're discontinuous - have lots of gaps in their endothelium. large fenistrae.
blood cells are common - as are KUPEFFER CELLS (macrophages) |
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what is expected to be found in the space of disse (perisinusoidal space)? as in, what cell type?
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Ito cells (stellate) - these normally store Vitamin A.
Note that they can become myofibroblasts and secrete collagen, making a fibrotic liver. |
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describing lobules - what different ways are they, and what do they tell us?
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can divide lobules up into:
the classic lobule: this is our traditional hexagon, with six triads surround it, with blood flowing from the triads to the central vein and bile flowing toward the triad. Portal Lobule: This forms a triangle around a single triad, using 3 central veins as ends. Liver Acinus: This forms a ring around 2 central veins and the two triads between them. |
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the portal lobule: what's it good for describing?
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bile movement.
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the liver acinus - what's it good for describing?
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great at talking about blood supply. this is where you have zone 1 (closest to the shared border), zone 2 (mid way), and zone 3 (furthest from the border, closest to the opposite ventral veins).
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In the liver acinus, zones 1 and 2 and 3: what happens in them? where is blood supply loss seen first?
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zone 1 gets the best blood flow, zone 3 gets the worst. So, zone 3 is the first to show ischemia when blood supply goes down.
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what does bile do?
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helps emulsify fats.
also, detoxifies bilirubin. |
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what's the order of bile ducts? what is the one in the triad?
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start with caniculus: between hepatocytes, moving toward triad.
just before arriving at triad, get INTRAHEPATIC traveling in the triad, get INTERLOBULAR then get R/L hepatic ducts, them hepatic bile duct. |
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how can you identify a canniculus?
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see a tube going between hepatocytes (not in the sinusoids), probably that.
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galbladder: what does it look like?
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when empty, seriously tortuous mucosa.
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what are the big white things in gallbladders?
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Rokitansky-Ashcoft sinuses - these are invaginated mucosa. can lead to gallstones.
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pancreas: what's an exocrine unit? what do you often see in the cells?
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40-50 cells. these are acinar cells, which line a lumen (which itself is lined by centroacinar cells).
see zymogen granules in the apical sides of the pyrmidal-shaped acinar cells, ready for release into the exocrine ducts. |
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how is the pancreas hormonally controlled? what about nerves?
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Secretin, made by the duodenum, tells the pancreas to release all sorts of fluid with lots of HCO3- in it (to balance acids), but not a lot of enzyme.
CCK secretion tells the pancreas to dump in pro-enzymes) nerves: sympathetics control the blood flow, parasympathetics control the release of things from the acinar/centroacinar cells. |