Mononuclear phagocytic leukocyte, 13–25 μm in diameter, with an ovoid or kidney‐shaped nucleus. Precursor to a macrophage, it is formed in the bone marrow from a promonocyte and is transported to tissues such as the lung and liver, where it develops into a macrophage.
Large white blood cell that ingest microbes, other cells and foreign matter.
A type of white blood cell.
A large phagocytic white blood cell which, when it enters a tissue, develops into a macrophage.
Also called monocyte macrophages. The round-nucleated cells that circulate in the blood. In summary they engulf and kill microorganisms, present antigen to the lymphocytes, kill certain tumor cells, and are involved in the regulation of inflammation.
These cells are often the first to encounter a foreign substance or pathogen or normal cell debris in the body. When they do, the material is taken up (engulfed) and degraded by means of oxidative and hydrolytic enzymatic attack. Peptides that result from the degradation of foreign protein are then bound to a monocyte protein called class II MHC (major histocompatibility complex) and this self-foreign complex then migrates to the surface of the cell where it is embedded into the cell membrane in such a way as to present the peptide to the outside of the cell. This positioning allows T lymphocytes to recognize (inspect) the peptide.
Whereas self-peptides derived from normal cellular debris are ignored, foreign peptides activate precursors of helper T cells to further mature into active, lymphokine-secreting helper T lymphocytes, also known as TH cells. When monocytes move out of the bloodstream and into the tissues they are then called macrophages.
A phagocytic white blood cell that engulfs and destroys cellular debris.
A white blood cell with a nucleus shaped like a kidney, which destroys bacterial cells.
Type of granular leukocyte (white blood cell) that functions in the ingestion of bacteria and other foreign particles.
A variety of white blood cell, 16-20 μn in diameter, with a kidney shaped nucleus and grayish-blue cytoplasm (when treated with Romanovsky stains). Its function is the ingestion of foreign particles, such as bacteria and tissue debris. There are normally 0.2-0.8 x 10⁹ monocytes per liter of blood.
A type of white blood cell which has a single kidney-shaped nucleus. Present in the tissues and lymphatic system as well as in the circulation, it ingests foreign particles such as tissue debris and bacteria. Monocytes are about 20 um in diameter, and 1 mm³ of blood contains around 7,500 of them, many times fewer than the five million erythrocytes (red blood cells).
A mononuclear phagocytic white blood cell derived from myeloid stem cells. Monocytes circulate in the bloodstream for about 24 hr and then move into tissues, at which point they mature into macrophages, which are long lived. Monocytes and macrophages are one of the first lines of defense in the inflammatory process. This network of fixed and mobile phagocytes that engulf foreign antigens and cell debris previously was called the reticuloendothelial system and is now referred to as the mononuclear phagocyte system (MPS).
Mononuclear phagocytes of the innate immune system involved in the inflammatory process.
A variety of white blood cell that is generated within the bone marrow.
A prominent variety of white blood cell, monocytes are phagocytes responsible for enveloping and consuming invading microorganisms. They hold a significant function within the immune system.