M2002_lecs48_50 - Liver and Biliary Tract Pathology Liver...

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Unformatted text preview: Liver and Biliary Tract Pathology Liver Pathology, Lectures 1, 2, 3- 1 - I. GENERAL MORPHOLOGIC & FUNCTIONAL PATTERNS OF HEPATIC INJURY A. ANATOMY 1. Gross Pathology The liver is the largest viscus of the body, usually contributing 1/50 of the entire body weight (1400-1600 g) in adults and a much larger proportion (about 1/20), in the newborn child. It does not fall into the pelvis because of its firm attachment to the diaphragm by the coronary ligament, left & right triangular ligaments, and attachment to anterior body wall by the falciform ligament. Two-thirds of the blood supply to the liver comes from the portal vein, the other third comes from the hepatic artery. Blood drains into the hepatic veins and enters the inferior vena cava. 2. Microscopic Architecture a. Lobule: Classic hexagonal structure with portal tracts at the periphery and central vein (=terminal hepatic venule) at the center. b. Acinus: (Newer concept based on the hepatic microcirculation). The acini are roughly triangular with the bases being the terminal branches of the portal vein and hepatic artery and apices are the central vein (terminal hepatic venule). The acinus is divided into zones: i. Zone 1: Adjacent to portal venous system, richest in oxygen and nutrient supply. ii. Zone 2: Intermediate between 1 & 3 iii. Zone 3: At the apex, adjacent to the terminal hepatic venules; and affected most by anoxia and most toxins. B. FUNCTION The hepatocyte is unrivaled by any other parenchymal cell type in functional diversity and complexity. 1. Metabolic glucose homeostatis, lipid metabolism 2. Synthetic albumin, coagulation proteins I, II, V, VII-XIII, specific binding proteins 3. Storage glycogen, triglycerides, iron, copper, lipid and soluble vitamins 4. Catabolic ammonia->urea, contain hormones + proteins, detoxification of many foreign compounds, drugs and chemicals 5. Excretory bile excretion 6. Survival agenesis of the liver is incompatible with life Liver and Biliary Tract Pathology Liver Pathology, Lectures 1, 2, 3- 2 - C. LABORATORY ASSESSMENT OF LIVER FUNCTION 1. Serum Transaminases : Damaged cells leak contents into the circulation AST = Aspartate aminotransferase (SGOT) ALT = Alanine aminotransferase (SGPT) 2. Alkaline Phosphatase : Enzyme that exists as different isoenzymes in the liver, bone and intestine. In cholestatic disorders there is de novo synthesis which leaks into the circulation by undefined mechanisms. 3. Gamma Glutamyl Transpeptidase (GGT ): Elevations in levels of this enzyme differentiate whether or not an elevated alkaline phosphatase is of liver or non-liver origin. GGT levels may be elevated in conditions other than liver disease such as in response to some chemicals and drugs, but when both GGT and alkaline phosphatase are elevated, the liver/biliary tree is the likely source of both of these elevated enzymes....
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This note was uploaded on 01/16/2012 for the course BI 200 taught by Professor Potter during the Fall '11 term at Montgomery College.

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M2002_lecs48_50 - Liver and Biliary Tract Pathology Liver...

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