The basic functional units of the liver are known as which structures?

• A. Lobules
• B. Alveoli
• C. Acini
• D. Glomeruli

Answer: (A)

Liver tissue is organized into hepatic lobules, the basic functional units. Each lobule is roughly hexagonal and centers on a central vein, with portal triads at each corner. Blood from the hepatic artery and portal vein flows through sinusoids between hepatocytes, allowing processing of nutrients, detoxification, and metabolic tasks, before draining into the central vein. Bile produced by hepatocytes is collected by canaliculi and ultimately drains into bile ducts in the portal triad. This arrangement lets each lobule carry out the liver’s core functions in a compact, repeating unit. Alveoli are small air sacs in the lungs, glomeruli are filtration units in the kidneys, and the term acini refers to secretory clusters in some other glands; while “hepatic acini” is used in some contexts to discuss metabolic zones, the standard basic structural unit is the lobule.