The cells that participate in the immune response with strong phagocytosis are macrophages. Macrophages are found in tissues and blood and destroy bacteria that invade the organism, phagocytose foreign particles, eliminate senescent and damaged cells and degenerated interstitial cells in the body, kill tumor cells, and at the same time participate in the immune response and help the organism to initiate the healing process. Macrophages in different locations in the organism have different shapes and names. Monocytes are found in the bloodstream and travel with the bloodstream to locations in the body where there is inflammation, pulmonary macrophages are active in the lungs, hepatic macrophages are active in the liver, and the brain is where glial cells are active. Macrophages must leave as soon as they have completed their task; remaining in place can have an impact on tissue recovery.