Organ
Liver
Metabolic organ receiving portal and arterial inflow
High-yield
The portal vein supplies most hepatic blood flow, commonly about three quarters. The hepatic artery supplies a smaller flow fraction but a substantial oxygen contribution; these proportions change with physiological conditions.
Overview
The liver occupies much of the right upper abdomen and extends across the epigastrium beneath the diaphragm. Portal blood brings absorbed substances from abdominal organs, while hepatic arterial blood supplements its oxygen supply. Hepatocytes process these inputs, synthesize circulating proteins and produce bile for intestinal delivery.
Reference facts
- Location
- Predominantly beneath the right hemidiaphragm, extending into the epigastrium and sometimes farther left; much of it is protected by the lower thoracic cage.
- Parts
- Surface lobes are right, left, caudate and quadrate; functional territories are described by portal segmentation and hepatic venous planes.
- Blood supply
- Hepatic portal venous inflow plus hepatic arterial inflow, with common variations in arterial origin and distribution.
- Innervation
- Hepatic sympathetic and vagal autonomic pathways; sensory referral from adjacent diaphragmatic surfaces may involve the phrenic nerve.
- Venous/Lymphatic drainage
- Hepatic veins and smaller caval channels drain into the inferior vena cava. Lymph reaches hilar and diaphragmatic pathways, not solely the porta hepatis.
- Relations
- Diaphragm superiorly; gastric, duodenal, gallbladder, renal/suprarenal and colic relationships on the visceral surface; cava closely related posteriorly.
- Function
- Regulates nutrient metabolism, stores glycogen and other reserves, synthesizes plasma proteins, metabolizes many drugs and hormones, and forms bile.
Clinical correlation
The liver's vascularity can make traumatic injury a major bleeding source. Portal-pedicle occlusion reduces arterial and portal inflow but does not directly occlude hepatic venous outflow. Shoulder referral may occur when nearby diaphragmatic tissue is irritated.
Frequently asked questions
Where is the liver located?
Predominantly beneath the right hemidiaphragm, extending into the epigastrium and sometimes farther left; much of it is protected by the lower thoracic cage.
What does the liver do?
Regulates nutrient metabolism, stores glycogen and other reserves, synthesizes plasma proteins, metabolizes many drugs and hormones, and forms bile.
What are the parts of the liver?
Surface lobes are right, left, caudate and quadrate; functional territories are described by portal segmentation and hepatic venous planes.
What is the blood supply of the liver?
The liver is supplied by the hepatic portal venous inflow plus hepatic arterial inflow, with common variations in arterial origin and distribution.