- 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
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