Macrophage

Definition

Macrophages are large white blood cells within tissues that engulf and digest cellular debris, foreign substances, microbes, and cancer cells. They play a crucial role in the immune system by identifying, phagocytizing, and presenting antigens to T cells.

5 Must Know Facts For Your Next Test

1. Macrophages originate from monocytes, a type of white blood cell found in the bloodstream.
2. They are essential for both innate immunity and initiating adaptive immunity.
3. In the respiratory tract, alveolar macrophages reside in the alveoli and help clear inhaled pathogens and particles.
4. Macrophages release cytokines that signal other immune cells to respond to infections.
5. Chronic inflammation due to persistent infection can lead to macrophage activation and tissue damage.

Review Questions

• What is the primary function of macrophages in the respiratory tract?
• How do macrophages contribute to both innate and adaptive immune responses?
• What role do alveolar macrophages play in maintaining respiratory health?

Related terms

Monocyte: A type of white blood cell that differentiates into macrophages or dendritic cells upon entering tissues.

Phagocytosis:

The process by which a cell engulfs particles such as bacteria or cellular debris.

Cytokine: Small proteins released by cells that have a specific effect on interactions and communications between cells.