Liver Functional unit Hepatocyte Hexagonal lobules Vascular sinusoids
Liver • • Functional unit: Hepatocyte Hexagonal lobules Vascular sinusoids 3/4/2021 Dr Jaria Fatahia
3/4/2021 Dr Jaria Fatahia
Liver lobules – hexagonal ures. atocytes radiate ard from a central vein ach of the six corners obule is a portal triad er sinusoids 3/4/2021 Dr Jaria Fatahia
• Hepatocytes produce bile • Bile flows through canals called bile canaliculi to a bile duct • Bile ducts leave the liver via the common hepatic duct 3/4/2021 Dr Jaria Fatahia
Bile • BILE – bile salts, bile pigments, cholesterol, neutral fats, phospholipids and electrolytes • Liver produces 0. 5 -1 l of bile daily 3/4/2021 Dr Jaria Fatahia
3/4/2021 Dr Jaria Fatahia
Functions • Metabolic ü Synthesis ü Breakdown ü Other functions – storage of vitamin A, D, B 12, F… • Excretion of waste products from bloodstream into bile • Vascular – storage of blood 3/4/2021 Dr Jaria Fatahia
Protein metabolism Ø Synthesis of amino acids Ø Formation of plasma proteins Albumins, globulins Clotting factors Ø Transamination & transpeptidation Ø Deamination Ø Urea ccle Ø Formation of nitrogen containing compounds 3/4/2021 Dr Jaria Fatahia
Protein metabolism • Produces albumin the major osmolar component of blood serum • Synthesizes angiotensinogen, the hormone responsible for raising blood pressure when activated by renin (enzyme released when the kidney senses low blood pressure) 3/4/2021 Dr Jaria Fatahia
Carbohydrate Metabolism Ø Formation & storage of glycogen Ø Conversion of glycogen to glucose Ø Gluconeogenesis Ø Conversion of fructose & galactose to glucose 3/4/2021 Dr Jaria Fatahia
Lipid Metabolism Ø Formation of ketone bodies Ø Formation of TG & VLDL Ø Cholesterol Ø Saturation & desaturation of FA Ø Uptake of plasma LDL Ø Bile, Bile salts, bile acids Ø Bile pigment metabolism 3/4/2021 Dr Jaria Fatahia
Breakdown • Breaks down insulin and other hormones • Breaks down hemoglobin • Breaks down or modifies toxic substances (methylation) → sometimes results in toxication • Converts ammonia to urea 3/4/2021 Dr Jaria Fatahia
Breakdown Ø Hb: ü Globin ü Iron ü Porphyrin part 3/4/2021 Dr Jaria Fatahia
3/4/2021 Dr Jaria Fatahia
3/4/2021 Dr Jaria Fatahia
3/4/2021 Dr Jaria Fatahia
Extravascular Pathway for RBC Destruction (Liver, Bone marrow, & Spleen) Phagocytosis & Lysis Hemoglobin Globin Heme Amino acids Fe 2+ Excreted Amino acid pool 3/4/2021 Bilirubin Dr Jaria Fatahia
Heme Degradation 3/4/2021 Dr Jaria Fatahia
3/4/2021 Dr Jaria Fatahia
Hemoglobin dissociates into Heme & globin Porphyrin ring is cleaved Oxidation of alpha methylene bridges Heme loses one molecule of CO & one atom of iron in ferric form • Biliverdin ( biliverdin reductase) • Bilirubin • • 3/4/2021 Dr Jaria Fatahia
Biliverdin 3/4/2021 Dr Jaria Fatahia
3/4/2021 Dr Jaria Fatahia
Conjugation 3/4/2021 Dr Jaria Fatahia
3/4/2021 Dr Jaria Fatahia
Liver Function Tests 3/4/2021 Dr Jaria Fatahia
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