. define hematopoiesis. where does it occur
extramedullary hematopoiesis the formation and development of blood cells outside the bone marrow, as in the spleen, liver, and lymph nodes. extramedullary hematopoiesis The production of blood cells in tissues other than bone marrow, e.g., in the liver or spleen. hematopoiesis he·ma·to·poi·e·sis (hē'mə-tō-poi-ē'sĭs, hĭ-māt'ə-) or he·mo·poi·e·sis (hē'mə-) n. The formation of blood or blood cells in the living body. Also called hematogenesis, sanguification. Dictionary.com Unabridged Based on the Random House Dictionary, © Random House, Inc. 2018. Cite This Source extramedullary hematopoiesis the formation and development of blood cells outside the bone marrow, as in the spleen, liver, and lymph nodes. Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved. Medical Definition of Hematopoiesis Hematopoiesis: The production of all types of blood cells including formation, development, and differentiation of blood cells. Prenatally, hematopoiesis occurs in the yolk sack, then in the liver, and lastly in the bone marrow. In the normal situation, hematopoiesis in adults occurs in the bone marrow and lymphatic tissues. All types of blood cells are derived from primitive cells that are pluripotent (they have the potential to develop into all types of blood cells). It occurs in severe or chronic anemias and other diseases that affect blood cell formation. Synonym: myeloid metaplasia. See also: hematopoiesis. extramedullary. situated or occurring outside any of the medullas including the medulla oblongata and the medullary cavities of the bones. extramedullary hematopoiesis. see extramedullary hematopoiesis. the formation of and development of blood cells outside the bone marrow, as in the spleen, liver and lymph nodes. fetal hematopoiesis. in embryogenesis migration of stem cells from the yolk sac blood islands sets up hematopoiesis in thymus, lymph nodes, liver and spleen. regenerative hematopoiesis increased hematopoietic activity in response to a need for more cells; indicated by the presence of a higher than normal proportion of immature forms in the peripheral blood. The process of producing new blood cells is called hematopoiesis. Cells that can become more than one type of cell are called stem cells. The beginning stem cell for hematopoiesis is a hematopoietic stem cell. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company. Cite This Source See also: hematopoiesis. extramedullary. situated or occurring outside any of the medullas including the medulla oblongata and the medullary cavities of the bones. extramedullary hematopoiesis. see extramedullary hematopoiesis. hematopoiesis. the formation and development of blood cells, usually taking place in the bone marrow. cyclic hematopoiesis of collies
The medical definition of Hematopoiesis is the production of all types of blood cells including formation, development, and differentiation of blood cells. It occurs in the yolk sack, then in the liver, and lastly in the bone marrow.