Common Hepatic Duct and Cystic Duct join to form the common bile duct.
The common bile duct opens into the duodenum.
Liver Lobules
Liver Lobules: Tiny, hexagonal, sesame seed-sized structures; functional units of the liver.
Portal Triad: Found at each corner of a liver lobule consisting of:
Hepatic Artery (brings oxygen-rich blood).
Hepatic Venule (branches from the portal vein, bringing nutrient-rich blood from the digestive organs).
Biliary Duct (carries bile).
Hepatocytes:
Arranged like bricks, interspersed with sinusoidal capillaries.
Functions include processing blood-borne nutrients, storing glucose as glycogen, storing fat-soluble vitamins (A, D), detoxifying ammonia into urea, and producing various plasma proteins.
Contains rough/smooth endoplasmic reticulum, Golgi bodies, peroxisomes, and mitochondria.
Bile Production and Function
Bile: Yellowish-green alkaline fluid produced by the liver (about 900 mL/day).
Bile Salts: Cholesterol derivatives; emulsify fats for absorption.
Bilirubin: Pigment formed from the breakdown of hemoglobin, giving bile its color.
Other components include cholesterol, triglycerides, phospholipids, and electrolytes.
Hepatoportal System: Recirculates 95% of bile salts back to the liver, aiding reuse.
Gallstones: Form from cholesterol crystallization due to an imbalance of cholesterol and bile salts, causing pain and potentially obstructive jaundice.
Common Diseases and Conditions
Obstructive Jaundice: Caused by bile duct blockage, leading to bile pigment deposition in the skin.
Hepatitis: Inflammation of the liver due to viral infection, drug toxicity, etc.
Cirrhosis: Chronic liver inflammation often due to alcoholism, leading to liver tissue replacement by fibrous tissue and potential liver failure.
Regenerative Capacity of the Liver
Regeneration: Liver regenerates to full size in 6-12 months after 80% removal, provided the source of injury is removed.
Liver Transplants: Necessary if the extent of damage is too severe; requires blood matching.
Gallbladder
Structure: Thin-walled muscular sac located beneath the liver, stores and concentrates bile.
Function: Releases bile through cystic duct into the common bile duct upon contraction, stimulated by cholecystokinin in response to fatty food in the duodenum.
Gallstones: Obstruct bile flow, leading to pain during gallbladder contraction; treatable by various methods.
Pancreas
Location: Retroperitoneal, in the J-shaped curvature of the stomach.
Structure includes the head (encircled by duodenum), body, and tail (near spleen).
Endocrine Function: Pancreatic islets produce insulin (lower blood glucose) and glucagon (increase blood glucose).
Exocrine Function: Acinar cells produce pancreatic juice (1200-1500 mL/day), a watery, alkaline fluid containing digestive enzymes.