Which term is used for macrophages located in the lungs?

• A. Alveolar cells
• B. Microglia
• C. Kupffer cells
• D. Osteoclasts

Answer: (A)

The concept here is naming the resident macrophages by location. In the lungs, macrophages that reside in the alveolar spaces are called alveolar macrophages (also known as dust cells). They sit in the air spaces and phagocytose inhaled particles, pathogens, and debris, helping keep the alveoli clean and functioning. This term specifically denotes the macrophage population in the lung, distinguishing them from other cell types that live in the alveolar walls. It’s important to note that alveolar cells refer to the alveolar epithelial cells (type I and type II pneumocytes) that line the alveoli, not macrophages. The other options refer to macrophages or related cells in different tissues—microglia in the brain, Kupffer cells in the liver, and osteoclasts in bone.