Changes

===Stem cell ===

===Stem cell ===

[[Erythrocytes|Erythrocytes]] develop from stem cells that give rise to precursors which eventually mature to form the erythrocyte. The first erythrocyte precursor, the proerythroblast, is derived from the Erythroid CFU ([[Haematopoiesis#Colony Forming Units|CFU-E]]) which has differentiated from the multipotential myeloid stem cell ([[Haematopoiesis#Colony Forming Units|CFU-GEMM]]). This process is controlled and influenced by a number of different factors including erythropoietin, IL-3, IL-4 and granulocyte-macrophage colony stimulating factor (GM-CSF).

[[Erythrocytes|Erythrocytes]] develop from stem cells that give rise to precursors which eventually mature to form the erythrocyte. The first erythrocyte precursor, the proerythroblast, is derived from the Erythroid CFU ([[Haematopoiesis - Overview#Colony Forming Units|CFU-E]]) which has differentiated from the multipotential myeloid stem cell ([[Haematopoiesis - Overview#Colony Forming Units|CFU-GEMM]]). This process is controlled and influenced by a number of different factors including erythropoietin, IL-3, IL-4 and granulocyte-macrophage colony stimulating factor (GM-CSF).

===Nomenclature===

===Nomenclature===

The main headings for this section refer to each stage in terms of a histological description. Proerythroblast, basophilic erythroblast, polychromatic erythroblast, orthochromatic erythroblast and polychromatophilic erythrocyte.

The main headings for this section refer to each stage in terms of a histological description. Proerythroblast, basophilic erythroblast, polychromatic erythroblast, orthochromatic erythroblast and polychromatophilic erythrocyte.

Another classification of the stages is based upon the [[Haematopoiesis#Colony Forming Units|CFU-E]] being referred to as ‘rubri’. This system gives all developing blood cell lineages similar names. For example the first stage for erythrocytes is referred to as a [rubri]blast and the first stage for lymphocytes is called a [lympho]blast. The stages for the erythrocyte are rubriblast, prorubriblast, rubricyte and metarubricye.

Another classification of the stages is based upon the [[Haematopoiesis - Overview#Colony Forming Units|CFU-E]] being referred to as ‘rubri’. This system gives all developing blood cell lineages similar names. For example the first stage for erythrocytes is referred to as a [rubri]blast and the first stage for lymphocytes is called a [lympho]blast. The stages for the erythrocyte are rubriblast, prorubriblast, rubricyte and metarubricye.

Finally the stages can also be named according to the development of the normoblast stage. This gives the stages pronormoblast, early normoblast, intermediate normoblast, late normoblast, polychromatic cell.

Finally the stages can also be named according to the development of the normoblast stage. This gives the stages pronormoblast, early normoblast, intermediate normoblast, late normoblast, polychromatic cell.

[[Image:Erythropoiesis pathway.jpg|right|thumb|100px|'''Erythropoiesis pathway''']]

[[Image:Erythropoiesis pathway.jpg|right|thumb|100px|'''Erythropoiesis pathway''']]

====Proerythroblast====

====Proerythroblast====

The first [[Erythrocytes|erythrocyte]] precursor produced directly from the [[Haematopoiesis#Colony Forming Units|CFU-GEMM]] under the influence of erythropoietin. It has a large nucleus with free ribosomes in the cytoplasm giving the cytoplasm a basophilic appearance.

The first [[Erythrocytes|erythrocyte]] precursor produced directly from the [[Haematopoiesis - Overview#Colony Forming Units|CFU-GEMM]] under the influence of erythropoietin. It has a large nucleus with free ribosomes in the cytoplasm giving the cytoplasm a basophilic appearance.

Alternative nomenclature: Pronormoblast or Rubriblast

Alternative nomenclature: Pronormoblast or Rubriblast