Array ( [0] => {{Short description|Process which produces red blood cells}} [1] => {{More citations needed|date=October 2019}} [2] => [[Image:Illu blood cell lineage.jpg|thumb|right|400px|[[Haematopoiesis]] [3] => {{Cite book [4] => | last1 = Le [5] => | first1 = Tao [6] => | first2 = Vikas [7] => | last2 = Bhushan [8] => | first3 = Neil [9] => | last3 = Vasan [10] => | title = First Aid for the USMLE Step 1: 2010 20th Anniversary Edition [11] => | location = USA [12] => | publisher = [[The McGraw-Hill Companies, Inc.]] [13] => | year = 2010 [14] => | pages = [https://archive.org/details/firstaidforusmle0000unse_r6p4/page/123 123] [15] => | isbn = 978-0-07-163340-6 [16] => | title-link = First Aid for the USMLE Step 1: 2010 20th Anniversary Edition [17] => }} [18] => ]] [19] => '''Erythropoiesis''' (from Greek 'erythro' meaning "red" and 'poiesis' "to make") is the process which produces [[red blood cell]]s (erythrocytes), which is the development from erythropoietic stem cell to mature red blood cell.{{cite book | chapter=Amino Acid and Heme Metabolism | date=2007-01-01 | doi=10.1016/B978-0-323-03410-4.50018-3 | pages=97–105 | quote=Erythropoiesis
Heme synthesis is coordinated with globin synthesis during erythropoiesis and as such does not occur in the mature erythrocyte. Erythropoiesis is the development of mature red blood cells from erythropoietic stem cells. The first cell that is morphologically recognizable in the red cell pathway is the proerythroblast. In the basophilic erythroblast, the nucleus becomes somewhat smaller, exhibiting a coarser appearance, and the cytoplasm becomes more basophilic owing to the presence of ribosomes. As the cell begins to produce hemoglobin, the cytoplasm attracts both basic and eosin stains and is called a polychromatophilic erythroblast. As maturation continues, the orthochromatophilic erythroblast extrudes its nucleus and the cell enters the circulation as a reticulocyte. As reticulocytes lose their polyribosomes, they become mature red blood cells.| title=Elsevier's Integrated Biochemistry | last1=Pelley | first1=John W. | isbn=9780323034104 }} [20] => [21] => It is stimulated by decreased O2 in circulation, which is detected by the [[kidney]]s, which then secrete the hormone [[erythropoietin]].Sherwood, L, Klansman, H, Yancey, P: ''Animal Physiology'', Brooks/Cole, Cengage Learning, 2005. This hormone stimulates proliferation and differentiation of red cell precursors, which activates increased erythropoiesis in the [[hemopoietic]] tissues, ultimately producing [[red blood cells]] (erythrocytes). In [[postnatal]] [[bird]]s and [[mammal]]s (including [[humans]]), this usually occurs within the [[red bone marrow]]. In the early [[fetus]], erythropoiesis takes place in the mesodermal cells of the [[yolk sac]]. By the third or fourth month, erythropoiesis moves to the liver.{{cite journal |vauthors=Palis J, Segel GB | title = Developmental biology of erythropoiesis | journal = Blood Rev. | volume = 12 | issue = 2 | pages = 106–14 |date=June 1998 | pmid = 9661799 | doi = 10.1016/S0268-960X(98)90022-4 | doi-access = }} After seven months, erythropoiesis occurs in the bone marrow. Increased levels of physical activity can cause an increase in erythropoiesis. [22] => {{Cite book [23] => | last1 = Le [24] => | first1 = Tao [25] => | first2 = Vikas [26] => | last2 = Bhushan [27] => | first3 = Neil [28] => | last3 = Vasan [29] => | title = First Aid for the USMLE Step 1: 2010 20th Anniversary Edition [30] => | location = USA [31] => | publisher = [[The McGraw-Hill Companies, Inc.]] [32] => | year = 2010 [33] => | pages = [https://archive.org/details/firstaidforusmle0000unse_r6p4/page/124 124] [34] => | isbn = 978-0-07-163340-6 [35] => | title-link = First Aid for the USMLE Step 1: 2010 20th Anniversary Edition [36] => }} [37] => However, in [[humans]] with certain [[diseases]] and in some [[animals]], erythropoiesis also occurs outside the [[bone marrow]], within the [[spleen]] or [[liver]]. This is termed ''[[Extramedullary hematopoiesis|extramedullary erythropoiesis]]''. [38] => [39] => The [[bone marrow]] of essentially all the [[bone]]s produces red blood cells until a person is around five [[years]] old. The [[tibia]] and [[femur]] cease to be important sites of [[hematopoiesis]] by about age 25; the [[vertebra]]e, [[Human sternum|sternum]], [[pelvis]] and [[rib]]s, and [[cranial bones]] continue to produce red blood cells throughout life. Up to the age of 20 years, RBCs are produced from red bone marrow of all the bones (long bones and all the flat bones). After the age of 20 years, RBCs are produced from membranous bones such as vertebrae, the sternum, ribs, scapulas, and the iliac bones. After 20 years of age, the shaft of the long bones becomes yellow bone marrow because of fat deposition and loses the erythropoietic function.{{Cite book |last1=Sembulingam |first1=K. |url=https://books.google.com/books?id=tdODr5fpxEAC&pg=PA71 |title=Essentials of Medical Physiology |last2=Sembulingam |first2=Prema |date=2012-09-30| page=71|publisher=JP Medical Ltd |isbn=978-93-5025-936-8 |language=en}} [40] => [41] => Comparison of erythrocyte production by marrow stem cell lines from old and young adult donors shows no significant differences.{{cite journal|doi=10.1016/0047-6374(79)90082-4|pmid=37376 |title=Proliferative capacity of erythropoietic stem cell lines and aging: An overview |date=1979 |last1=Harrison |first1=David E. |journal=Mechanisms of Ageing and Development |volume=9 |issue=5–6 |pages=409–426 |s2cid=31601624 }} This finding implies that little or none of the proliferative capacity of the erythropoietic stem cells is exhausted by a lifetime of normal functioning. [42] => [43] => == Erythrocyte differentiation == [44] => In the process of red blood corpuscle maturation, a cell undergoes a series of ''[[cellular differentiation|differentiation]]s''. The following stages of development all occur within the [[bone marrow]]: [45] => # A [[hemocytoblast]], a [[multipotent]] [[hematopoietic]] [[stem cell]], becomes [46] => # a common myeloid progenitor or a [[multipotent stem cell]], then [47] => # a unipotent stem cell, then [48] => # a [[pronormoblast]] (also commonly called an proerythroblast or a rubriblast), then [49] => # a basophilic or early normoblast (also commonly called an erythroblast), then [50] => # a polychromatophilic or intermediate normoblast, then [51] => # an orthochromatic or late normoblast. At this stage the nucleus is expelled before the cell becomes [52] => # a [[reticulocyte]]. (These cells still contain RNA and are also called "immature red blood cells") [53] => [54] => The cell is released from the bone marrow after Stage 7, and so in newly circulating red blood cells there are about 1% reticulocytes. After one to two days, these ultimately become "erythrocytes" or mature red blood cells. [55] => [56] => These stages correspond to specific appearances of the cell when stained with [[Wright's stain]] and examined by light microscopy, and correspond to other biochemical changes. [57] => [58] => In the process of maturation, a basophilic pronormoblast is converted from a cell with a large [[cell nucleus|nucleus]] and a volume of 900 [[Femtolitre|fL]] to an [[enucleation (microbiology)|enucleated]] disc with a volume of 95 fL. By the reticulocyte stage, the cell has extruded its nucleus, but is still capable of producing hemoglobin. [59] => [60] => Essential for the maturation of red blood cells are [[Vitamin B12|Vitamin B12]] (cobalamin) and [[Vitamin B9|Vitamin B9]] (folate). Lack of either causes maturation failure in the process of erythropoiesis, which manifests clinically as [[reticulocytopenia]], an abnormally low amount of reticulocytes. [61] => [62] => ==Characteristics seen in erythrocytes during erythropoiesis== [63] => As they mature, a number of erythrocyte characteristics change: [64] => [65] => * The overall size of the erythroid precursor cell decreases, increasing the cytoplasmic to nucleus (C:N) ratio. The nuclear diameter decreases and chromatin condenses with the staining reaction progressing from purplish red to dark blue at the final nuclear stage of the orthochromatic erythroblast, prior to nuclear ejection. [66] => * The colour of the cytoplasm changes from blue at proerythroblast and basophilic stages to a pinkish red as a result of the increasing expression of haemoglobin as the cell develops. [67] => * The nucleus is initially large in size and contains open [[chromatin]]. As red blood cells mature, the size of the nucleus decreases, until it finally disappears with the condensation of the chromatin material.Textbook of Physiology by Dr. A. K. Jain reprint 2006-2007 3rd edition. [68] => [69] => ==Mechanism of erythropoiesis== [70] => The production of all blood cells begins with the haemocytoblast, a multipotent haematopoietic stem cell. Haemocytoblasts have the greatest powers of self-renewal of any adult cell. They are found in the bone marrow and can be mobilised into the circulating blood when needed. [71] => Some haemocytoblasts differentiate into common myeloid progenitor cells, which go on to produce erythrocytes, as well as mast cells, megakaryocytes and myeloblasts. [72] => The process by which common myeloid progenitor cells become fully mature red blood cells involves several stages. First, they become normoblasts (aka eryhthroblasts), which are normally present in the bone marrow only. [73] => Then, they lose their nucleus as they mature into reticulocytes, which can be thought of as immature red blood cells. Some of these are released into the peripheral circulation. [74] => Finally, reticulocytes lose their remaining organelles as they mature into erythrocytes-which are fully mature red blood cells. The average lifespan of a red blood cell is approximately 120 days. [75] => During this maturation process, there is nuclear extrusion – i.e. mature erythrocytes have no nucleus. Nucleated red blood cells present in a sample of bone marrow can indicate the release of incompletely developed cells. This can occur in pathology such as thalassaemia, severe anaemia or haematological malignancy. [76] => [77] => ==Regulation of erythropoiesis== [78] => A feedback loop involving [[erythropoietin]] helps regulate the process of erythropoiesis so that, in non-disease states, the production of red blood cells is equal to the destruction of red blood cells and the red blood cell number is sufficient to sustain adequate tissue oxygen levels but not so high as to cause sludging, [[thrombosis]], or [[stroke]]. Erythropoietin is produced in the kidney and liver in response to low oxygen levels. In addition, erythropoietin is bound by circulating red blood cells; low circulating numbers lead to a relatively high level of unbound erythropoietin, which stimulates production in the bone marrow. [79] => [80] => Recent studies have also shown that the peptide hormone [[hepcidin]] may play a role in the regulation of hemoglobin production, and thus affect erythropoiesis. The liver produces hepcidin. Hepcidin controls iron absorption in the gastrointestinal tract and iron release from reticuloendothelial tissue. Iron must be released from [[macrophages]] in the bone marrow to be incorporated into the heme group of [[hemoglobin]] in erythrocytes. There are colony forming units that the cells follow during their formation. These cells are referred to as the committed cells including the granulocyte monocyte colony forming units. [81] => [82] => The secretion of hepcidin is inhibited by another hormone, [[erythroferrone]], produced by erythroblasts in response to erythropoietin, and identified in 2014.{{cite web | website=The Hematologist | url=http://www.hematology.org/Thehematologist/Years-Best/3599.aspx | title=Erythroferrone: A Missing Link in Iron Regulation | publisher=American Society of Hematology | access-date=26 August 2015 | author=Koury, M.J. | date=2015-01-13 | archive-date=2019-01-28 | archive-url=https://web.archive.org/web/20190128180220/http://www.hematology.org/Thehematologist/Years-Best/3599.aspx | url-status=dead }}{{cite journal | vauthors = Kautz L, Jung G, Valore EV, Rivella S, Nemeth E, Ganz T | title = Identification of erythroferrone as an erythroid regulator of iron metabolism | journal = Nature Genetics | volume = 46 | issue = 7 | pages = 678–84 | date = Jul 2014 | pmid = 24880340 | pmc = 4104984 | doi = 10.1038/ng.2996 }} It appears that this links erythropoietin-driven eyrthropoiesis with the iron mobilization needed for hemoglobin synthesis. [83] => [84] => Loss of function of the erythropoietin receptor or JAK2 in mice cells causes failure in erythropoiesis, so production of red blood cells in embryos and growth is disrupted. If there is no systemic feedback inhibition, for example, the diminishment or absence of suppressors of cytokine signaling proteins, [[giantism]] may result as shown in [[mice]] models.{{cite journal |vauthors=Nicolas G, Bennoun M, Porteu A, Mativet S, Beaumont C, Grandchamp B, Sirito M, Sawadogo M, Kahn A, Vaulont S | title = Severe iron deficiency anemia in transgenic mice expressing liver hepcidin | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 99 | issue = 7 | pages = 4596–601 |date=April 2002 | pmid = 11930010 | pmc = 123693 | doi = 10.1073/pnas.072632499 | bibcode = 2002PNAS...99.4596N | doi-access = free }}{{cite journal |author1=Michael Föller |author2=Stephan M. Huber |author3=Florian Lang | title = Erythrocyte programmed cell death. | journal = IUBMB Life | volume = 60 | issue = 10 | pages = 661–668 |date=August 2008 | pmid = 18720418 | doi = 10.1002/iub.106 |s2cid=41603762 | doi-access = free }}{{dead link|date=February 2019|bot=medic}}{{cbignore|bot=medic}} [85] => [86] => == Stress erythropoiesis == [87] => In addition to the steady state erythropoiesis, acute anemia probably stimulates another response which results in rapid development of new red blood cells. This has been studied in rats and happens in the liver through the activation of the BMP4-dependent stress erythropoiesis pathway.{{Cite journal|last1=Paulson|first1=Robert F.|last2=Shi|first2=Lei|last3=Wu|first3=Dai-Chen|date=May 2011|title=Stress erythropoiesis: new signals and new stress progenitor cells|journal=Current Opinion in Hematology|volume=18|issue=3|pages=139–145|doi=10.1097/MOH.0b013e32834521c8|issn=1065-6251|pmc=3099455|pmid=21372709}} [88] => [89] => ==See also== [90] => * [[Anemia]]: a condition with an abnormally low level of functional [[haemoglobin]] [91] => * [[Polycythemia]]: a condition with an abnormally high level of red blood cells [92] => * [[Dyserythropoiesis]]: a problem with the development of red blood cells [93] => [94] => == References == [95] => {{Reflist}} [96] => [97] => ==External links== [98] => * [https://web.archive.org/web/20071112103437/http://www.healthsystem.virginia.edu/internet/hematology/HessIDB/home.cfm Microscopic Hematology] [99] => * [https://web.archive.org/web/20090429025520/http://www.ndsu.nodak.edu/instruct/tcolvill/435/erythrocytes.htm More information on erythropoiesis] [100] => [101] => {{Blood physiology}} [102] => {{Authority control}} [103] => [104] => [[Category:Hematopoiesis]] [] => )
good wiki

Erythropoiesis

Erythropoiesis is the process of producing red blood cells (erythrocytes) in the body. This process takes place in the bone marrow, specifically in the trabecular region of long bones and in the axial skeleton's marrow.

More about us

About

This process takes place in the bone marrow, specifically in the trabecular region of long bones and in the axial skeleton's marrow. Erythropoiesis is regulated by the hormone erythropoietin (EPO), which is produced mainly by the kidneys in response to low oxygen levels in the blood. The process starts with the differentiation of hematopoietic stem cells into erythroblasts, which then mature through several stages to become fully functional red blood cells. During this process, the cells undergo various changes, including the loss of the nucleus and other organelles to increase their capacity to carry oxygen. Erythropoiesis is highly regulated and is influenced by factors such as nutrient availability, hormone levels, and genetic disorders. Understanding the process of erythropoiesis is crucial for diagnosing and treating various disorders related to red blood cell production, such as anemia and erythropoietin deficiency.

Expert Team

Vivamus eget neque lacus. Pellentesque egauris ex.

Award winning agency

Lorem ipsum, dolor sit amet consectetur elitorceat .

10 Year Exp.

Pellen tesque eget, mauris lorem iupsum neque lacus.

You might be interested in

Bird

Birds are a group of warm-blooded vertebrates characterized by feathers, beaks, wings, and the ability to lay eggs.

Chromatin

Chromatin is the material that makes up the chromosomes in eukaryotic cells.

Diseases

Erythropoietin

Erythropoietin (EPO) is a hormone produced mainly by the kidneys that regulates the production of red blood cells in the body.

Hemoglobin

Hemoglobin is a protein found in red blood cells that is responsible for carrying oxygen from the lungs to the tissues and organs of the body.

Kidney

The kidney is an essential organ in the human body responsible for filtering waste products and excess water from the bloodstream, producing urine, and maintaining proper levels of electrolytes and fluids.

Liver

The liver is an organ in the human body located in the upper right abdomen.

Macrophages

Mammal

The Wikipedia page for Mammal provides an overview of this diverse group of animals that includes humans, as well as cats, dogs, whales, and many others.