Which tiny structures located throughout the body help fight infection?

Which tiny structures located throughout the body help fight infection?

• A. Lymph nodes
• B. Lungs
• C. Spleen
• D. Adrenal glands

Answer: (A)

Lymph nodes are the small, bean-shaped structures spread throughout the body that act as surveillance centers for the immune system. As immune fluid called lymph drains through these nodes, specialized cells—B cells, T cells, and macrophages—scan for pathogens, present bits of invaders to other immune cells, and coordinate a targeted response. This distributed network allows the body to detect and respond to infections in many tissues quickly, which is why these tiny structures are key defenders. Lungs do provide some immune defenses, like alveolar macrophages, but they’re actual organs rather than scattered tiny structures. The spleen supports immune responses by filtering blood but is a single, not widely distributed, organ. The adrenal glands release hormones that can modulate immunity, but they aren’t primary infection-fighting structures.

Lymph nodes are the small, bean-shaped structures spread throughout the body that act as surveillance centers for the immune system. As immune fluid called lymph drains through these nodes, specialized cells—B cells, T cells, and macrophages—scan for pathogens, present bits of invaders to other immune cells, and coordinate a targeted response. This distributed network allows the body to detect and respond to infections in many tissues quickly, which is why these tiny structures are key defenders.

Lungs do provide some immune defenses, like alveolar macrophages, but they’re actual organs rather than scattered tiny structures. The spleen supports immune responses by filtering blood but is a single, not widely distributed, organ. The adrenal glands release hormones that can modulate immunity, but they aren’t primary infection-fighting structures.