When a macrophage ingests foreign material, what structure does the material initially become trapped in?

When a macrophage ingests foreign material, the material becomes initially trapped in a phagosome. This process begins with the macrophage extending its plasma membrane around the foreign particle, effectively encasing it and forming this specialized compartment called a phagosome.

The phagosome is an intracellular vesicle that contains the engulfed material, and it is crucial for the subsequent stages of digestion and processing of the ingested substances. Once the phagosome forms, it typically fuses with lysosomes to form a phagolysosome, where the contents are degraded by hydrolytic enzymes. This mechanism is a key part of the immune response, as it helps the macrophage to eliminate pathogens and other foreign particles effectively.

Understanding the role of the phagosome is essential in grasping the overall process of phagocytosis, which is an important immune function in the body.