Information about Erythropoiesis
Erythropoiesis is the process by which red blood cells (erythrocytes) are produced. In human adults, this usually occurs within the 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 spleen and liver. In humans with certain diseases and in some animals, erythropoeiesis also occurs outside the bone marrow, within the spleen or liver. This is termed extramedullary erythropoiesis.
The tibia and femur cease to be important sites of hematopoiesis by about age 25; the vertebrae, sternum, pelvis and ribs continue to produce red blood cells throughout life.
After these stages, the cell is released from the bone marrow, and ultimately becomes an "erythrocyte" or mature red blood cell circulating in the peripheral blood.
These stages correspond to specific appearances of the cell when stained with Wright's stain and examined by light microscopy, but correspond to other biochemical changes.
In the process of maturation a basophilic pronormoblast is converted from a cell with a large nucleus and a volume of 900 µm3 to an enucleated disc with a volume of 95 µm3. By the reticulocyte stage, the cell has extruded its nucleus, but is still capable of producing hemoglobin.
Recent studies have also shown that the peptide hormone hepcidin may play a role in the regulation of hemoglobin production, and thus effect erthropoiesis. The liver produces hepcidin. Hepcidin controls iron absorption in the gastrointestinal tract and iron release from reticuloendothelial tissue.1 Iron must be released from macrophages in the bone marrow to be incorporated into the heme group of hemoglobin in erythrocytes.
The tibia and femur cease to be important sites of hematopoiesis by about age 25; the vertebrae, sternum, pelvis and ribs continue to produce red blood cells throughout life.
Erythrocyte differentiation
In the process of red blood cell maturation, a cell undergoes a series of differentiations. The following stages of development all occur within the bone marrow:- pluripotent hematopoietic stem cell
- multipotent stem cell
- unipotential stem cell
- pronormoblast
- basophilic normoblast/early normoblast
- polychromatophilic normoblast/intermediate normoblast
- orthochromatic normoblast/late normoblast
- reticulocyte
After these stages, the cell is released from the bone marrow, and ultimately becomes an "erythrocyte" or mature red blood cell circulating in the peripheral blood.
These stages correspond to specific appearances of the cell when stained with Wright's stain and examined by light microscopy, but correspond to other biochemical changes.
In the process of maturation a basophilic pronormoblast is converted from a cell with a large nucleus and a volume of 900 µm3 to an enucleated disc with a volume of 95 µm3. By the reticulocyte stage, the cell has extruded its nucleus, but is still capable of producing hemoglobin.
Regulation of erythropoesis
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. Erythropoeitin is produced in the kidney and liver in response to low oxygen levels. In addition, erythropoeitin is bound by circulating red blood cells; low circulating numbers lead to a relatively high level of unbound erythropoeitin, which stimulates production in the bone marrow.Recent studies have also shown that the peptide hormone hepcidin may play a role in the regulation of hemoglobin production, and thus effect erthropoiesis. The liver produces hepcidin. Hepcidin controls iron absorption in the gastrointestinal tract and iron release from reticuloendothelial tissue.1 Iron must be released from macrophages in the bone marrow to be incorporated into the heme group of hemoglobin in erythrocytes.
See also
- Anemia: a condition with an abnormally low level of functional haemoglobin
- Polycythemia: a condition with an abnormally high level of red blood cells
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Red blood cells are the most common type of blood cell and the vertebrate body's principal means of delivering oxygen from the lungs or gills to body tissues via the blood.
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Bone marrow (or medulla ossea) is the soft tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells.
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Marrow types
There are two types of bone marrow: red marrow (also known as myeloid tissue) and..... Click the link for more information.
The yolk sac is the first element seen in the gestational sac during pregnancy, usually at 5 weeks gestation.
It is a critical landmark, identifying a true gestation sac.
It is quite echogenic (light) to ultrasound, and reliably seen early.
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It is a critical landmark, identifying a true gestation sac.
It is quite echogenic (light) to ultrasound, and reliably seen early.
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The spleen is an organ located in the abdomen of the human body, where it functions in the destruction of old red blood cells and holding a small reservoir of blood. It is regarded as one of the centers of activity of the reticuloendothelial system (part of the immune system).
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liver is an organ present in vertebrates and some other animals. It plays a major role in metabolism and has a number of functions in the body, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, and detoxification.
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tibia is the larger of the two bones in the leg below the knee in vertebrates.
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In humans
The tibia or shin bone, in human anatomy, is found medial (towards the middle) and anterior (towards the front) to the other such bone, the fibula...... Click the link for more information.
The femur or thigh bone is the longest, most voluminous, and strongest bone of mammalian bodies. It forms part of the hip and part of the knee.
The word femur is Latin for thigh.
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The word femur is Latin for thigh.
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Haematopoiesis (from Ancient Greek: haima blood; poiesis to make) (or hematopoiesis in the United States; sometimes also haemopoiesis or hemopoiesis) is the formation of blood cellular components.
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The Vertebral Column (singular: vertebra) are the individual irregular bones that make up the spinal column (aka ischis) — a flexuous and flexible column.
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sternum (from Greek στέρνον, sternon, "chest" and hebrew pronounced "Shamokin" also meaning chest) or breastbone is a long, flat bone located in the center of the thorax (chest).
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pelvis (pl. pelvises or pelves) is the bony structure located at the base of the spine (properly known as the caudal end). The pelvis incorporates the socket portion of the hip joint for each leg (in bipeds) or hind leg (in quadrupeds).
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RIB can mean:
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- Rigid-hulled inflatable boat
- Romanian International Bank
- Routing Information Base
- This article is about the bones called ribs. For other meanings, see rib (disambiguation).
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Cellular differentiation is a concept from developmental biology describing the process by which cells acquire a "type". The morphology of a cell may change dramatically during differentiation, but the genetic material remains the same, with few exceptions.
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Bone marrow (or medulla ossea) is the soft tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells.
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Marrow types
There are two types of bone marrow: red marrow (also known as myeloid tissue) and..... Click the link for more information.
Stem cells are primal cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types.
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A proerythroblast (or rubriblast, or pronormoblast) is the earliest of four stages in development of the normoblast.
In histology, it is very difficult to distinguish it from the other "blast" cells (lymphoblast, myeloblast, monoblast, and megakaryoblast.
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In histology, it is very difficult to distinguish it from the other "blast" cells (lymphoblast, myeloblast, monoblast, and megakaryoblast.
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An erythroblast is a type of red blood cell which still retains a cell nucleus. It is the immediate precursor of a normal erythrocyte.
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Nomenclature
The term normoblast is sometimes used as a synonym for erythroblast, but at other times it is considered a subcategory...... Click the link for more information.
An erythroblast is a type of red blood cell which still retains a cell nucleus. It is the immediate precursor of a normal erythrocyte.
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Nomenclature
The term normoblast is sometimes used as a synonym for erythroblast, but at other times it is considered a subcategory...... Click the link for more information.
Reticulocytes are immature red blood cells, typically composing about 1% of the red cells in the human body. Reticulocytes develop and mature in the red bone marrow and then circulate for about a day in the blood stream before developing into mature red blood cells.
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Wright's stain is a technique in histology that is used to make the differences between cells visible under light microscopy. It is used in the examination of peripheral blood smears and bone marrow aspirates.
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nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth ER (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles]]
In cell biology, the nucleus (pl.
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In cell biology, the nucleus (pl.
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Erythropoietin (IPA pronunciation: [ɪˌɹɪθ.ɹoˈpo.ɪ.tɪn], alternative pronunciations:
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Hepcidin is a recently discovered peptide hormone produced by the liver, that appears to be the master regulator of iron homeostasis in humans and other mammals.[1]
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Macrophages (Greek: "big eaters", from makros "large" + phagein "eat") are cells within the tissues that originate from specific white blood cells called monocytes.
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Hemoglobin, also spelled haemoglobin and abbreviated Hb, is the iron-containing oxygen-transport metalloprotein in the red blood cells of the blood in vertebrates and other animals.
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Anemia
Classification & external resources
ICD-10 D 50. -D 64.
ICD-9 280 - 285
DiseasesDB 663
MedlinePlus 000560
eMedicine med/132 emerg/808 emerg/734
MeSH D000740
Anemia (AmE) or anæmia/anaemia
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Classification & external resources
ICD-10 D 50. -D 64.
ICD-9 280 - 285
DiseasesDB 663
MedlinePlus 000560
eMedicine med/132 emerg/808 emerg/734
MeSH D000740
Anemia (AmE) or anæmia/anaemia
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Hemoglobin, also spelled haemoglobin and abbreviated Hb, is the iron-containing oxygen-transport metalloprotein in the red blood cells of the blood in vertebrates and other animals.
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MeSH D011086 Polycythemia is a condition in which there is a net increase in the total number of red blood cells in the body. The overproduction of red blood cells may be due to a primary process in the bone marrow (a so-called myeloproliferative syndrome), or it may be a
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