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Myelopoiesis
In hematology, myelopoiesis in the broadest sense of the term is the production of bone marrow and of all cells that arise from it, namely, all blood cells. In a narrower sense, myelopoiesis also refers specifically to the regulated formation of myeloid leukocytes ( myelocytes), including eosinophilic granulocytes, basophilic granulocytes, neutrophilic granulocytes, and monocytes. The common myeloid progenitor can differentiate in the bone marrow into red blood cells and megakaryocytes (leading to platelets) as well as mast cells and myeloblasts, the latter leading to the myelocytic line (granulocytes) and to monocytes, macrophages, and dendritic cells of the innate immune system. The granulocytes, also called polymorphonuclear leukocytes because of their multilobed nuclei, are three short lived cell types including eosinophils, basophils, and neutrophils. A granulocyte differentiates into a distinct cell type by a process called granulopoiesis. In this process it first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myeloid
Myeloid tissue, in the bone marrow sense of the word '' myeloid'' ('' myelo-'' + '' -oid''), is tissue of bone marrow, of bone marrow cell lineage, or resembling bone marrow, and myelogenous tissue (''myelo-'' + '' -genous'') is any tissue of, or arising from, bone marrow; in these senses the terms are usually used synonymously, as for example with chronic myeloid/myelogenous leukemia. In hematopoiesis, myeloid cells, or myelogenous cells are blood cells that arise from a progenitor cell for granulocytes, monocytes, erythrocytes, or platelets (the common myeloid progenitor, that is, CMP or CFU-GEMM), or in a narrower sense also often used, specifically from the lineage of the myeloblast (the myelocytes, monocytes, and their daughter types). Thus, although all blood cells, even lymphocytes, are normally born in the bone marrow in adults, myeloid cells in the narrowest sense of the term can be distinguished from lymphoid cells, that is, lymphocytes, which come from co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematopoiesis
Haematopoiesis (; ; also hematopoiesis in American English, sometimes h(a)emopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. In a healthy adult human, roughly ten billion () to a hundred billion () new blood cells are produced per day, in order to maintain steady state levels in the peripheral circulation.Semester 4 medical lectures at Uppsala University 2008 by Leif Jansson Process Haematopoietic stem cells (HSCs) Haematopoietic stem cells (HSCs) reside in the medulla of the bone ( bone marrow) and have the unique ability to give rise to all of the different mature blood cell types and tissues. HSCs are self-renewing cells: when they differentiate, at least some of their daughter cells remain as HSCs so the pool of stem cells is not depleted. This phenomenon is called asymmetric division. The other daughters of HSCs ( myeloid and lymphoid progenitor cells) can follow any of the other diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granulopoiesis
Granulopoiesis (or granulocytopoiesis) is a part of haematopoiesis, that leads to the production of granulocytes. A granulocyte, also referred to as a polymorphonuclear leukocyte (PMN), is a type of white blood cell that has multi lobed nuclei, usually containing three lobes, and has a significant amount of cytoplasmic granules within the cell. Granulopoiesis takes place in the bone marrow. It leads to the production of three types of mature granulocytes: neutrophils (most abundant, making up to 60% of all white blood cells), eosinophils (up to 4%) and basophils (up to 1%). Stages of granulocyte development Granulopoiesis is often divided into two parts; 1) Granulocyte lineage determination and 2) Committed granulopoiesis. Granulocyte lineage determination Granulopoiesis, as well as the rest of haematopoiesis, begins from a haematopoietic stem cell. These are multipotent cells that reside in the bone marrow niche and have the ability to give rise to all haematopoietic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myeloblast
The myeloblast is a unipotent white blood cell which differentiates into the effectors of the granulocyte series. It is found in the bone marrow. Stimulation of myeloblasts by G-CSF and other cytokines triggers maturation, differentiation, proliferation and cell survival. Structure Myeloblasts reside extravascularly in the bone marrow. Hematopoiesis takes place in the extravascular cavities between the sinuses of the marrow. The wall of the sinuses is composed of two different types of cells, endothelial cells and adventitial reticular cells. The hemopoietic cells are aligned in cords or wedges between these sinuses, with myeloblasts and other granular progenitors concentrated in the subcortical regions of these hemopoietic cords. Myeloblasts are rather small cells with a diameter between 14 and 18μm. The major part is occupied by a large oval nucleus composed of very fine nonaggregated chromatin and possessing 3 or more nucleoli. The cytoplasm has a basophilic character an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrophages
Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. This self-protection method can be contrasted with that employed by Natural killer cell, Natural Killer cells. This process of engulfment and digestion is called phagocytosis; it acts to defend the host against infection and injury. Macrophages are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microglia, and others), but all are part of the mononuclear phagocyte system. Besides phagocytosis, they play a critical role in nonspecific defense (innate immunity) and also help initiate specific defense mechanisms (adapti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promonocytes
A promonocyte (or premonocyte) is a cell arising from a monoblast and developing into a monocyte. See also * Pluripotential hemopoietic stem cell Hematopoietic stem cells (HSCs) are the stem cells that give rise to other blood cells. This process is called haematopoiesis. In vertebrates, the first definitive HSCs arise from the ventral endothelial wall of the embryonic aorta within the (m ... Additional images Image:Hematopoiesis (human) diagram en.svg, Hematopoiesis Image:Promonocyte.png, Schematic image of a promonocyte External links "Monocyte Development" at tulane.edu* - "Bone marrow smear" Blood cells Immune system {{cell-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band Cell
A band cell (also called band neutrophil, band form or stab cell) is a cell undergoing granulopoiesis, derived from a metamyelocyte, and leading to a mature granulocyte. It is characterized by having a curved but not lobular nucleus. The term "band cell" implies a granulocytic lineage (e.g., neutrophils). Clinical significance Band neutrophils are an intermediary step prior to the complete maturation of segmented neutrophils. Polymorphonuclear neutrophils are initially released from the bone marrow as band cells. As the immature neutrophils become activated or exposed to pathogens, their nucleus will take on a segmented appearance. An increase in the number of these immature neutrophils in circulation can be indicative of an infection for which they are being called to fight against, or some inflammatory process. The increase of band cells in the circulation is called bandemia and is a "left shift" process. Blood reference ranges for neutrophilic band cells in adults ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutrophil
Neutrophils are a type of phagocytic white blood cell and part of innate immunity. More specifically, they form the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. Their functions vary in different animals. They are also known as neutrocytes, heterophils or polymorphonuclear leukocytes. They are formed from stem cells in the bone marrow and differentiated into subpopulations of neutrophil-killers and neutrophil-cagers. They are short-lived (between 5 and 135 hours, see ) and highly mobile, as they can enter parts of tissue where other cells/molecules cannot. Neutrophils may be subdivided into segmented neutrophils and banded neutrophils (or bands). They form part of the polymorphonuclear cells family (PMNs) together with basophils and eosinophils. The name ''neutrophil'' derives from staining characteristics on hematoxylin and eosin ( H&E) histological or cytological preparations. Whereas basophilic white blood cells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basophil
Basophils are a type of white blood cell White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are genera .... Basophils are the least common type of granulocyte, representing about 0.5% to 1% of circulating white blood cells. They are the largest type of granulocyte. They are responsible for inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases, including anaphylaxis, asthma, atopic dermatitis and Hay Fever, hay fever. They also produce compounds that coordinate immune responses, including histamine and serotonin that induce inflammation, and heparin that prevents Coagulation, blood clotting, although there are less than that found in mast cell granules. Mast cells were once thought to be basophils that migrated from the blood into their r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eosinophil
Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. Along with mast cells and basophils, they also control mechanisms associated with allergy and asthma. They are granulocytes that develop during hematopoiesis in the bone marrow before migrating into blood, after which they are terminally differentiated and do not multiply. These cells are eosinophilic or "acid-loving" due to their large acidophilic cytoplasmic granules, which show their affinity for acids by their affinity to coal tar dyes: Normally transparent, it is this affinity that causes them to appear brick-red after staining with eosin, a red dye, using the Romanowsky method. The staining is concentrated in small granules within the cellular cytoplasm, which contain many chemical mediators, such as eosinophil peroxidase, ribonucl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Innate Immune System
The innate immune system or nonspecific immune system is one of the two main immunity strategies in vertebrates (the other being the adaptive immune system). The innate immune system is an alternate defense strategy and is the dominant immune system response found in plants, fungi, prokaryotes, and invertebrates (see #Beyond vertebrates, Beyond vertebrates).. The major functions of the innate immune system are to: * recruit immune cells to infection sites by producing chemical factors, including chemical mediators called cytokines * activate the complement cascade to identify bacteria, activate cells, and promote clearance of immune complex, antibody complexes or dead cells * identify and remove foreign substances present in organs, tissues, blood and lymph, by specialized white blood cells * activate the adaptive immune system through antigen presentation * act as a physical and chemical barrier to infectious agents; via physical measures such as skin and mucus, and chemical me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendritic Cell
A dendritic cell (DC) is an antigen-presenting cell (also known as an ''accessory cell'') of the mammalian immune system. A DC's main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and adaptive immune systems. Dendritic cells are present in tissues that are in contact with the body's external environment, such as the skin, and the inner lining of the nose, lungs, stomach and intestines. They can also be found in an immature and mature state in the blood. Once activated, they migrate to the lymph nodes, where they interact with T cells and B cells to initiate and shape the adaptive immune response. At certain development stages they grow branched projections, the '' dendrites,'' that give the cell its name (δένδρον or déndron being Greek for 'tree'). While similar in appearance to the dendrites of neurons, these are structures distinct from them. Immature dendr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
