Introduction of Liver

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Information about Introduction of Liver

Published on March 2, 2009

Author: drsasank


Liver & Gall Bladder : Liver & Gall Bladder Dr. R. Sasank Professor of Pathology Siddhartha Medical college,Vijayawada Human liver Chart : Human liver Chart Prologue : Prologue The liver and its companion biliary tree and gallbladder are considered together because of their anatomic proximity, their interrelated functions, and the overlapping features of some of the diseases that affect these organs Residing at the crossroads between the digestive tract and the rest of the body, the liver has the enormous task of maintaining the body's metabolic homeostasis. Introduction : Introduction The liver is the largest gland in the body. Normal adult liver weighs 1400 to 1600 gm, representing 2.5% of body weight. It is located behind the ribcage in the right upper quadrant of the abdominal cavity, resting just below the diaphragm. It performs an astonishingly large number of tasks that impact all body systems. It has tremendous regeneration Capacity Introduction …..Contd : Introduction …..Contd It processes dietary amino acids , carbohydrates, lipids, and vitamins; It synthesizes serum proteins It detoxify the endogenous waste products and xenobiotics & excrete into bile . Thus liver is vulnerable to a wide variety of metabolic, toxic, microbial, and circulatory insults Location of Liver : Location of Liver The mature liver lies in the right hypochondrium under the rib cage and extends from the right fifth intercostal space at the midclavicular line to just below the costal margin. It projects slightly below the costal margin at the right inter-costal line and under the xyphoid process in the midline. Location of Liver Chart : Location of Liver Chart Topographic Division of the liver : Topographic Division of the liver The conventional division of the liver into The right lobe, The left lobe, The caudate lobe The quadrate lobes This does not correspond to the functional lobes or segments of the liver. Micro architecture : Micro architecture Classically, the liver has been divided into 1- to 2-mm diameter hexagonal lobules Lobule oriented around terminal hepatic veins tributaries Portal tracts are at periphery of lobule Hepatocytes present at Centrilobular around central vein (Hepatic Periportal near the portal tract Acinar architectural Zones : Acinar architectural Zones In the "acinus," the parenchyma is divided into three zones, zone 1 being closest to the vascular supply, zone 2 being intermediate zone 3 abutting the terminal hepatic venule, and. Importance of Zonation is of considerable metabolic consequence, A lobular gradient of activity exists for many hepatic enzymes hepatic injury exhibit a zonal distribution. Comparison Lobular Vs Acinar : Comparison Lobular Vs Acinar Lobule vs Acinus Structure : Lobule vs Acinus Structure Simple Acinus & Zonal arrangement of hepatocytes. : Simple Acinus & Zonal arrangement of hepatocytes. Hepatic Parenchyma-1 : Hepatic Parenchyma-1 The hepatic parenchyma is organized into cribiform (pierced with holes as in a sieve ), anastomosing sheets or "plates" of hepatocytes Hepatocytes immediately abutting the portal tract are referred to as the limiting plate, forming a rim around the mesenchyme of the portal tract. There is a radial orientation of the hepatocyte cords around the terminal hepatic vein. Hepatocytes exhibit variation in size, Nuclei may vary in size, number, and ploidy, particularly with advancing age. Uninucleate, Hepatic Parenchyma-2 : Hepatic Parenchyma-2 Between the cords of hepatocytes are vascular sinusoids. Blood traverses the sinusoids and exits into the terminal hepatic vein through orifices of vein wall. Hepatocytes are bathed on 2 sides by well-mixed portal venous and hepatic arterial blood. The sinusoids are lined by fenestrated and discontinuous endothelial cells, which demarcate an extrasinusoidal space of Disse, into which protrude abundant microvilli of hepatocytes. Scattered Kupffer cells of the There are scattered fat-containing perisinusoidal stellate cells in the space of Disse. They stellate cells play a role in metabolism of vitamin A and are transformed into collagen-producing myofibroblasts in inflammation Liver Cell plates : Liver Cell plates Schematic liver : Schematic liver Sinusoid Diagramatic : Sinusoid Diagramatic Kupffer Cells in sinusoids : Kupffer Cells in sinusoids Portal tract : Portal tract Biliary pole of hepatocyte : Biliary pole of hepatocyte Bile Duct Micro : Bile Duct Micro Blood Supply : Blood Supply Incoming blood- 25% of cardiac output—arrives via the Portal vein it is 60% to 70% of hepatic blood flow 30% to 40% from hepatic artery through the hilum, the "gateway" of the liver (porta hepatis). Outgoing Blood- collected into ramifications of the hepatic vein, which exits by the "back door" of the liver into the closely apposed inferior vena cava. Circulation of liver : Circulation of liver Heptic artery carries oxygen-rich blood from the aorta . The portal vein carries blood containing digested food from the small intestine. These blood vessels subdivide in the liver repeatedly, terminating in very small capillaries. Each capillary leads to a lobule. Zonal Flow of Blood : Zonal Flow of Blood Classical lobule-Flow of blood : Classical lobule-Flow of blood Hepatic Micro Circulation : Hepatic Micro Circulation Hepatic Micro Circulatory Cone : Hepatic Micro Circulatory Cone Liver- Functions : Liver- Functions Vascular functions, including formation of lymph and the hepatic phagocytic system. Metabolic achievements in control of synthesis and utilization of carbohydrates, lipids and proteins. Secretory and excretory functions, particularly with respect to the synthesis of secretion of bile. Metabolic Functions of Liver : Metabolic Functions of Liver The liver is the central organ of glucose homeostasis, maintaining blood glucose levels by glycogenolysis and gluconeogenesis. Synthetic functions : Synthetic functions Most serum proteins, including Albumin Blood coagulation factors Complement, Acute phase reactants binding proteins for iron, copper, and vitamin A Plasma Proteins synthesized : Plasma Proteins synthesized Catabolic functions : Catabolic functions Endogenous substances, including Hormones Serum proteins, are catabolized by the liver to maintain a balance between their production and their elimination. The liver is also the principal site for the detoxification of foreign compounds (xenobiotics). Storage Functions : Storage Functions The liver is an important storage site for Glycogen, Triglycerides, Iron, copper, Lipid-soluble vitamins. Excretory Functions: : Excretory Functions: The principal excretory product of the liver is bile, an aqueous mixture of conjugated bilirubin, bile acids, phospholipids, cholesterol electrolytes. Bile not only provides a repository for the products of heme catabolism but is also vital for fat absorption in the small intestine. Laboratory Evaluation of Liver -1 : Laboratory Evaluation of Liver -1 Laboratory Evaluation of Liver -2 : Laboratory Evaluation of Liver -2 Liver- Recap : Liver- Recap Largest Organ Lobular/ Acinar architecture Portal Triad Double blood Supply Functions Metabolic Synthetic Excretory Storage Catabolic

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