What are macrophages found in the liver called?

• A. Kupffer cells
• B. Hepatocytes
• C. Stellate cells
• D. Endothelial cells

Answer: (A)

Macrophages in the liver are called Kupffer cells. They are specialized macrophages that reside in the hepatic sinusoids, lining the blood vessels where portal blood from the gut flows in. This position lets them act as sentinels, filtering bacteria, endotoxins, debris, and aged red blood cells from the bloodstream. Kupffer cells originate from circulating monocytes and differentiate once they settle in the liver, where they actively phagocytose invaders and worn-out cells and can present antigens to help coordinate immune responses. This role and location distinguish them from other liver cells: hepatocytes perform metabolic and secretory functions; stellate (Ito) cells store vitamin A and can contribute to fibrosis; endothelial cells line the sinusoids and form the vascular lining.