monocyte

…occur in two varieties—granulocytes and monocytes—and ingest and break down microorganisms and foreign particles. The circulating blood functions as a conduit, bringing the various kinds of cells to the regions of the body in which they are needed: red cells to tissues requiring oxygen, platelets to sites of injury, lymphocytes…

Monocytes are the largest cells of the blood (averaging 15–18 μm in diameter), and they make up about 7 percent of the leukocytes. The nucleus is relatively big and tends to be indented or folded rather than multilobed. The cytoplasm contains large numbers of…

…from the blood is the monocyte, a mononuclear cell larger than the lymphocyte and with different potentialities. These migratory cells can divide and, when appropriately stimulated, can transform into highly phagocytic macrophages. The reaction of the blood and connective-tissue cells to injury is called inflammation and is usually accompanied by…

…and other organs produce the monocytes (4–8 percent of the white cells). The platelets, which are small cellular fragments rather than complete cells, are formed from bits of the cytoplasm of the giant cells (megakaryocytes) of the bone marrow.

These precursors develop into monocytes and dendritic cells, phagocytic cells that are released into the bloodstream. Some monocytes and dendritic cells remain in the general blood circulation, but most of them enter body tissues. In tissues, monocytes develop into much larger phagocytic cells known as macrophages. The great majority…

…following an inflammatory reaction, the monocytes may increase in number, and subsequently the lymphocytes will become more numerous.

…of white blood cells, the monocytes, which eventually mature into cell-eating macrophages. Macrophages usually become more prevalent at the site of injury only after days or weeks and are a cellular hallmark of chronic inflammation.