Essential Knowledge of the Liver and Biliary System 

Overview 

The liver and biliary system play key roles in metabolism, digestion, detoxification, and immune function. Understanding their anatomy, blood supply, and clinical relevance is essential for patient care and disease management. 


1. Liver 

Location & Gross Anatomy 

Largest internal organ (~1.5 kg) 
Located in the right upper quadrant (RUQ) beneath the diaphragm 
Extends into the left upper quadrant 
Divided anatomically into right and left lobes by the falciform ligament 



Microscopic Anatomy 
Functional unit: hepatic lobule 

Key structures: 
Hepatocytes 
Sinusoids 
Central vein 
Portal triad (hepatic artery, portal vein, bile duct) 

Blood Supply 

Dual blood supply: 
Portal vein (≈75%): nutrient-rich blood from GI tract 
Hepatic artery (≈25%): oxygenated blood 
Venous drainage via hepatic veins → inferior vena cava (IVC) 

Functions 

Metabolism of carbohydrates, proteins, and fats 
Bile production and secretion 
Detoxification of drugs and toxins 
Storage of glycogen, vitamins (A, D, B12), iron 
Synthesis of plasma proteins (albumin, clotting factors) 
Immune function (Kupffer cells) 

Clinical Correlates 

Hepatitis (viral, autoimmune, toxic) 
Cirrhosis and portal hypertension 
Liver function tests (ALT, AST, ALP, bilirubin, albumin, INR) 

2. Gallbladder 

Anatomy & Location 

Pear-shaped sac (7–10 cm) 
Located on the undersurface of the liver 
Divided into fundus, body, and neck 



Function 

Stores and concentrates bile 
Releases bile into the duodenum during fat digestion 
Blood Supply 
Cystic artery (branch of right hepatic artery) 

Clinical Correlates 

Gallstones (cholelithiasis) 
Cholecystitis 
Murphy’s sign 
Cholecystectomy (gallbladder removal) 

3. Biliary Duct System 

Components 

Right and left hepatic ducts → common hepatic duct 
Cystic duct + common hepatic duct → common bile duct (CBD) 
CBD joins pancreatic duct at the ampulla of Vater 
Empties into duodenum via sphincter of Oddi 



Function 

Transports bile from liver and gallbladder to the duodenum 

Clinical Correlates 

Obstructive jaundice 
Choledocholithiasis (stones in CBD) 
Ascending cholangitis (medical emergency) 
ERCP used for diagnosis and treatment 

4. Spleen 

Anatomy & Location 

Located in left upper quadrant 
Posterolateral to the stomach 
Highly vascular, encapsulated organ 



Functions 

Filters blood 
Removes old or damaged red blood cells 
Immune response (lymphocyte production) 
Platelet and blood reservoir 

Blood Supply 

Splenic artery (branch of celiac trunk) 
Splenic vein → portal vein 

Clinical Correlates 

Splenomegaly (e.g., portal hypertension, infections) 
Hypersplenism 
Risk of rupture with trauma 
Post-splenectomy infection risk (encapsulated organisms) 

5. Integrated Clinical Concepts 

Portal circulation links GI tract, spleen, and liver 
Liver disease can affect coagulation, immunity, and metabolism 
Biliary obstruction leads to jaundice, pale stools, dark urine 

Nurses should monitor: 

Liver function tests 
Signs of bleeding 
Mental status (hepatic encephalopathy causes confusion) 
Nutritional status 

Summary Table