Phagocytosis is the engulfment and destruction of extracellularly-derived materials by phagocytic cells, such as macrophages and neutrophils. The foreign body is ingested by the cell forming a phagosome which moves toward a lysosome. The lysosome and phagosome fuse, releasing lysosomal enzymes into the phagosome. The ingested material is digested before being released from the cell.