Digestive Glands and Liver II Flashcards
(27 cards)
Classic organization of Hepatic Lobules
central venule in the center of the lobule; portal triads are at the angles
Portal organization of hepatic lobules
3 central venules of adjacent lobules form triangle. Portions of the bile canaliculi of the 3 lobules drain into the same bile duct
Liver Acinus organization of hepatic lobules
Includes 3 zones defined by hepatic tissue receiving blood from a branch of the hepatic artery conducting blood to opposite veins. Metabolic gradient extends from hepatic triad to central vein.
Where is the portal triad located?
at angles (corners) of the classic lobule
What are the 3 components of the portal triad?
Branch of hepatic artery, branch of portal vein and bile duct
Space of Disse
Separates hepatic cells from endothelial cells. Active in transfer b/w blood and parenchyma. Contains types 1,III, and IV collagens.
Space of Mall
continuous w/ space of Disse. Drains in to lymphatics.
Organization of the hepatic lobule
Epithelial parenchyma is composed of hepatic cells irregularly arranged as plates seen on edges as cell cords and radially arranged around the central vein.
Canal of Hering
Receives bile from canaliculus and carries bile to bile ductule.
Limiting plate
What the lymphatic vessels peirce through to drain the Space of Mall. They surround the portal space.
Hepatic plates
formed by single rows of hepatocytes.
Hepatocyte
polyhedral, central nucleus w/ one or more nucleoli. Cytoplasm may contain glycogen, fat droplets, and pigment granules.
Kupffer cells
Phagoctytic cell, derived from monocytes. Lines hepatic sinusoids
Where are Perisinusoidal cells located?
Space of Disse
Function of Perisinusoidal cells
Store vit. A. Produce collagen fibers and extracellular matrix components.
What do the perisinusoidal cells do during Cirrhosis?
Transform into myofibroblasts. Become the main collagen type I producing cells - stimulated by cytokines from hepatocytes, Kupffer cells and lymphocytes.
What are the two afferent blood vessels in the liver?
portal vein and hepatic artery
What is the efferent vessel of the liver?
central vein
Functions of the liver
remove bile pigments from the blood and secrete them to bile. store glycogen. convert fats and proteins to carbs. maintain constancy of blood glucose level. chief site of a.a deamination w/ urea byproduct. metabolizing fat and store. synthesize plasma proteins (fibrinogen, prothrombin, and albumin). Store essential vitamins A, D, B2,3,4,12 and K. Serving as an embryonic hematopoietic organ. Ethanol metabolism. Detox of drugs, steroids, vit. A and D, FA, and carcinogens.
Ethanol metabolizing pathway
ethanol -> acetaladehyde -> hepatocyte injury v
acetate (w/ acetaldehyde dehydrogenase) in the mito
What is the major pigment of bile?
bilirubin
Components of bile
Bile acids (cholic and chenodeoxycholic, deoxcycholic and lithocholic acids); water and electrolytes; cholesterol and phospholipids (lecithin); pigments and organic molecules
Pathway for production of bile
Hb released from damaged RBS, Hb phagocytized by macrophages and split into globin and Heme. Heme ring is open to free iron - heme is transported in the blood by transferrin forming a straight chain of pyrrole nuclei. Heme is converted by heme oxygenase into biliverdin. Biliberdin -> free (unconjugated) bilirubin.
Pathway for secretion of bile (from free bilirubin)
free bilirubin is transported attached to plasma albumin to liver hepatocytes. Free bilirubin is released from plasma ablubin w/i the liver cells and conjugated which is secreted (active transport) into the intestine. Conj. bilirubin in the intestine is converted by bacterial action into urobilinogen.
