Liver, gall bladder, and pancreas histology Flashcards
What comprises the portal triad?
A hepatic artery, portal vein, and bile duct.
What is the lymph vessel is a portal triad derived from?
The space of Disse.
What cell type makes up most hepatocytes?
Bi-nucleate cells that are polyploid (4N).
What are the three surfaces of a hepatocyte?
Baso-lateral, sinusoidal, and cannicular. (Also have the space of Disse for lymphatics)
What is the flow of bile in a portal triad?
Bile flows counter-current (bile flows towards the portal triad while the blood flows towards the central vein).
What are the three types of liver lobules?
Classic lobule, portal lobule, and acinar lobule.
What is the function of classic lobules?
Endocrine function of the liver (fibrinogen, albumin, glucose produced and secreted elsewhere).
What is the function of portal lobules?
Exocrine function of the liver (secretes bile and other products into bile duct).
What is the function of acinar lobules?
Reflects gradient of metabolic activity in the liver (comprised of three zones).
What is the shape of a classic lobule?
They are polygonal in shape.
What is the organization of a classic lobule?
Portal canals at the periphery and a central vein in the center.
What is the shape of a portal lobule?
They are triangular in shape.
What is the organization of a portal lobule?
Portal canal (portal triad) at the center and central veins in the peripheral apices (drain bile into the bile cannaliculi in the triad).
What is the organization of a acinar lobule?
Portal triads and central veins at the periphery.
What are the zones of acinar lobules based on?
Whether a hepatocyte is peripheral to the central vein or peripheral to the portal triad (i.e. how close a cell is to the blood supply).
What are the three zones of an acinar lobule?
Zone 1 (periportal), Zone 2 (mid-region), and Zone 3 (centro-lobular). Zone 1 is closest to the blood supply and Zone 3 is farthest.
Which zone of an acinar lobule is the last to die?
Zone 1. Hepatocytes here receive the most nutrients and blood,
Which zone of an acinar lobule is the first to die?
Zone 3. Is the farthest away from nutrients/blood.
What cytological differences are present between the zones of an acinar lobule?
Metabolic differences (metabolic gradient in the liver). Includes carbohydrate metabolism, drug metabolism, ect).
In a healthy liver what is the capacity for hepatocyte regeneration?
Cells in all three zones will regenerate.
In a liver with zonal damage (pathology) what is the capacity for hepatocyte regeneration?
There is selective regeneration of damaged zones as opposed to regeneration in all zones.
What kind of abnormal regeneration occurs in hepatic cirrhosis?
CT elements do not cooperate, resulting in altered hepatic structure and compromised parenchymal function.
Where are receptor-ligand complexes of endocrine hormones targeted to the liver (insulin, glucagon,ect) degraded?
In the lysosomes of hepatocytes. An absence of lysosomes leads to a variety of disorders.
Where are the apoproteins for lipoprotein complexes synthesized?
In the rER of hepatocytes.
What is the function of the smooth ER in hepatocytes?
Synthesis of cholesterol/phospholipids, esterification of FFA, convert T3 to T4, drug metabolism, synthesis of cholic acid, and Ca2+ storage.
What do hepatic peroxisomes metabolize?
Purine catabolism (produces uric acid), alcohols, ect.
What kinds of receptors do Kupffer cell posses?
Fc and complement receptors to phagocytose immune complexes, bacteria, and non-immune particulates.
What is another function of kupffer cells?
They bind and degrade hemoglobin to bilirubin (shared function with the spleen).
What are Ito cells?
Hepatic lipocytes.
What do Ito cells store?
They can act as reserves of vitamin A (lipid soluble).
What is another function of Ito cells?
They can take up lipophilic/membranolytic molecules that lysosomes can’t process/are damaged by (ex. detergents,ect).
What are the intrahepatic biliary channels?
Bile canaliculus to terminal ductules to interlobular bile ducts.
What is gallbladder mucosa similar to?
It is similar to GI mucosa except that it doesn’t posses a submucosa (lamina propria followed by the muscularr layer).
What are the four major cell types of the pancreas?
Alpha, beta, delta, and PP cells.
What do alpha cells produce?
Glucagon
What do beta cells produce?
Insulin and amylin
What do delta cells produce?
Somatostopin
What do PP cells produce?
Pancreatic polypeptide
What are the three minor pancreatic cell types?
Delta-1, EC cells, and epsilon cells.
