Liver Anatomy and Functions: Detoxification, Metabolism, Storage, and More

Anatomy

• Location: Right upper quadrant, beneath diaphragm, protected by ribs
• Size: ~1.5 kg (3.3 lbs); largest solid organ
• Lobes: Right, left, caudate, quadrate
• Blood supply: Dual — hepatic artery (25% flow, 50% O₂) + portal vein (75% flow, nutrient-rich)
• Functional unit: Hepatic lobule (central vein → portal triads)

Six Major Functions

1. Detoxification: Phase I (CYP450 oxidation), Phase II (conjugation) → biliary/renal excretion. Alcohol, drugs, ammonia → urea.
2. Metabolism:
   • Carbohydrates: glycogenesis, glycogenolysis, gluconeogenesis
   • Proteins: synthesis (albumin, clotting factors, acute-phase), deamination, urea cycle
   • Lipids: β-oxidation, ketogenesis, lipoprotein assembly (VLDL, HDL), cholesterol synthesis
3. Storage: Glycogen (80–100g), vitamins A/D/B12/K, iron (ferritin), copper
4. Bile production: 600–1000 mL/day; bile acids emulsify fats, enable fat-soluble vitamin absorption; excretory route for bilirubin, cholesterol, drugs
5. Immunity: Kupffer cells (resident macrophages) clear gut-derived bacteria/endotoxin; acute-phase proteins; complement
6. Hemostasis: Synthesizes all clotting factors (except vWF), anticoagulants (antithrombin, protein C/S), fibrinolytic factors

Clinical Correlates

• Liver failure → coagulopathy, encephalopathy, ascites, jaundice, hypoglycemia
• Regeneration capacity: up to 70% resection regrows