- Largest gland in the body
- Weight: ∼ 1.2–1.5 kg in adults (2.6–3.3 pounds)
- Consists of four lobes:
- Right (largest)
- Typically divided into 8 segments
- Surrounded by the Glisson capsule
- Porta hepatis structures
- Location: under the diaphragm in the right upper abdomen.
- Extends from the fifth intercostal space to the right costal margin in the midclavicular line
- Percussed at the fifth intercostal space: see
- Connects liver to abdominal wall
- Divides liver into right (larger) and left (smaller) lobes
- Contains round ligament of liver
- Connects liver to lesser curvature of the stomach
- Contains gastric arteries
As part of the liver's dual blood supply, the portal vein allows tissue to remain oxygenated and preserve function in the event of an obstructed hepatic artery.
- Glisson capsule and serosa: lower intercostal nerves
- Parenchyma: hepatic plexus
- Visceral peritoneum: Serosa that covers the liver.
- Lobules: Sheets of connective tissue divide the liver into small hexagonal units called lobules, which consists of:
- Mostly consists of hepatocytes
Sinusoids are large capillaries lined with highly fenestrated endothelial cells: blood flows through the sinusoids and empties into the central vein of each lobule
- Absorption of nutrients from blood and secretion of products synthesized by special carriers into the blood
- Contain Kupffer cells (a type of macrophage)
- The plasma-filled space between the sinusoids and hepatocytes is called the perisinusoidal space (of Disse); : contains hepatic stellate cells (Ito cells), which store vitamin A; and are the main source of extracellular matrix production in liver injury (formation of scar tissue → fibrosis)
- Apical surface of hepatocytes faces bile canaliculi
- Zone I – periportal zone (affected first in viral hepatitis and toxic substance ingestion)
- Zone II – intermediate zone (affected in )
Zone III – pericentral vein/centrilobular zone (affected first in ischemia and ; most sensitive to metabolic toxins (e.g., halothane, CCl4))
- Has the highest amount of cytochrome P-450
|Energy metabolism|| |
|Detoxification and clearance/excretion|
Example of : A constant amount of alcohol is metabolized per unit time (∼ 1 ounce of alcohol per hour).
- Oxidation of ethanol to acetaldehyde by alcohol dehydrogenase (ADH): competitive inhibition of ADH by fomepizole; → treatment of methanol or ethylene glycol poisoning to prevent the formation of toxic metabolites 
Oxidation of acetaldehyde to acetate by acetaldehyde dehydrogenase
- Competitive inhibition of acetaldehyde dehydrogenase by disulfiram; → treatment of alcohol use disorder: acetaldehyde builds up fast after alcohol consumption and causes hangover symptoms 
- Other drugs (e.g., metronidazole) have a disulfiram-like effect; , which is why the concomitant use of alcohol and antibiotics is not recommended.
- Ligation of acetate and coenzyme A to acetyl-CoA by thiokinase under ATP consumption
When large quantities of alcohol are consumed, acetaldehyde builds up faster than it can be metabolized by ADH. Excess acetaldehyde plays a major role in hangover symptoms.
- Hepatic infection
- Hepatic tumors
- iron overload:
- copper overload:
- : increased liver glycogen
- Black liver due to