OIA2004 REVIEW OF LIVER

Liver

The body’s largest metabolic organ, responsible for detoxification, metabolism, and bile secretion.

Hepatic Portal Vein

Transports nutrient-rich but oxygen-poor blood from the GIT to the liver for processing.

First-Pass Metabolism

The process where orally administered drugs are metabolized in the liver before reaching systemic circulation.

Hepatic Lobules

Functional units of the liver containing hepatocytes, sinusoids, and Kupffer cells.

Bile

A digestive fluid secreted by the liver that aids in fat digestion and absorption.

Dual Blood Supply

Liver receives 75% of blood from the portal vein and 25% from the hepatic artery.

Sinusoids

Liver capillaries with high permeability, allowing large molecules to exchange between blood and hepatocytes.

Kupffer Cells

Specialized macrophages in the liver that engulf bacteria and worn-out red blood cells.

Hepatic Triad

Consists of a branch of the hepatic artery, hepatic portal vein, and bile duct.

Space of Disse

Small space between hepatocytes and endothelial cells, important for nutrient exchange.

Detoxification

The liver removes toxins, drugs, and metabolic waste from the blood.

Bile Production

Helps in the digestion and emulsification of fats.

Plasma Protein Synthesis

Produces albumin, clotting factors, and transport proteins.

Iron Storage

Stores iron as ferritin and regulates its metabolism.

Vitamin Storage

Stores vitamins A, D, and K for metabolic functions.

Glycogenesis

Conversion of excess glucose into glycogen for storage.

Glycogenolysis

Breakdown of glycogen into glucose when needed.

Gluconeogenesis

Synthesis of glucose from non-carbohydrate sources like amino acids.

Insulin and Glucagon Regulation

The liver maintains blood glucose homeostasis by responding to insulin and glucagon.

Amino Acid Transamination

Conversion of amino acids using enzymes like ALT and AST.

Urea Cycle

Converts toxic ammonia into urea for excretion.

Albumin Synthesis

Maintains oncotic pressure and transports molecules in the blood.

Clotting Factor Production

Produces factors II, VII, IX, and X, which are vitamin K-dependent.

Lipogenesis

Converts excess carbohydrates into triglycerides.

Beta-Oxidation

Breaks down fatty acids into Acetyl-CoA for energy.

Lipoprotein Synthesis

Produces LDL, HDL, VLDL, and chylomicrons for lipid transport.

Cholesterol Homeostasis

Regulates cholesterol levels through bile excretion.

Bile Salts

Emulsify fats for easier digestion by lipase.

Micelle Formation

Helps absorb fat-soluble vitamins (A, D, E, K).

Enterohepatic Circulation

Recycles 95% of bile salts back to the liver.

Gallstones

Form due to cholesterol imbalance in bile.

Phase I Metabolism

Oxidation, reduction, and hydrolysis reactions (e.g., CYP450 enzymes).

Phase II Metabolism

Conjugation reactions (e.g., glucuronidation, sulfation).

Prodrugs

Inactive drugs converted into active metabolites in the liver (e.g., enalapril → enalaprilat).

Drug-Induced Liver Injury

Caused by NSAIDs, acetaminophen, statins, antibiotics, etc.

Liver Cirrhosis

Chronic scarring of the liver leading to portal hypertension.

Hepatic Encephalopathy

Neurological dysfunction due to ammonia buildup in the blood.

Steatorrhea

Fatty stools due to bile production or absorption defects.

Hepatocellular Carcinoma (HCC)

Primary liver cancer, often due to chronic hepatitis or cirrhosis.

Jaundice

Yellowing of the skin due to bilirubin accumulation.