Erythrocyte Series Flashcards
Progenitor cell from which erythrocytes are derived
CFU-GEMM (aka common myeloid progenitor)
Major function of mature erythrocytes
To carry Hb
Site of production of erythropoietin
Kidney
Stimuli for production of erythropoietin
Tissue hypoxia
Mode of action of erythropoietin production when stimulated
Tissue hypoxia → kidney secretes EPO → ↑ plasma EPO → acts upon earliest cell committed to erythroid series to differentiate into rubriblast
- Also promotes early release of reticulocytes into BM
- Also inhibits apoptosis (programmed cell death)
First cell identifiable as being in erythrocyte series
Rubriblast
Nuclear, chromatin, and cytoplasmic appearance on Wright stain
- Pronormoblast/rubriblast
N: Round to slightly oval
Chromatin: Fine
Cyto: Dark blue
Nuclear, chromatin, and cytoplasmic appearance on Wright stain
- Basophilic normoblast/prorubricyte
N: Round to slightly oval
Chromatin: Slightly condensed
Cyto: Dark blue
Nuclear, chromatin, and cytoplasmic appearance on Wright stain
- Polychromatic normoblast/rubricyte
N: Round
Chromatin: Quite condensed
Cyto: Gray-blue (hemoglobinization)
Nuclear, chromatin, and cytoplasmic appearance on Wright stain
- Orthochromic normoblast/metarubricyte
N: Round
Chromatin: Fully condensed
Cyto: More pink or salmon
Nuclear, chromatin, and cytoplasmic appearance on Wright stain
- Polychromatic erythrocyte/reticulocyte (retic)
N: None
Chromatin: None
Cyto: Slightly more blue/purple than mature RBC
Nuclear, chromatin, and cytoplasmic appearance on Wright stain
- Erythrocyte
N: None
Chromatin: None
Cyto: Salmon w/ central pallor 1/3 of diameter
Maturation stage for when Hb synthesis begins (evident by special methods)
Basophilic normoblast (prorubricyte)
Maturation stage for when Hb can be detected by light microscopy
Polychromatic normoblast (rubricyte)
Period of time, under normal conditions, that marrow retic remains in BM prior to release in PB
Remains a BM retic for 2 more days, unless an increased need for more RBCs (“stress” or “shift” retic)
Period of time, under normal conditions, that blood retics continue to mature in blood after its release from BM
Released in circulation and matures 1 more day before becoming fully hemoglobinized
Size (in microns) of normal red cell
6-8 microns
Lifespan of normal red cell
120 +/- 10 days
Reasons for RBC senescence
- All cells deteriorate overtime due to ↓ activity of many enzymes
- B/c it’s non-nucleated, RBCs are unable to generate new proteins/enzymes
- Depletion of enzymes leads to loss of normal biconcave disc shape → spherical (can’t circulate normally through small splenic cords) → phagocytized by RES
Diminished delivery of O2 to tissues, as evidenced by pallor, malaise, and dyspnea; may be caused by blood loss, ↓ RBC production, or ↑ RBC destruction (shortened lifespan)
Anemia
Natural cell death characterized by nuclear condensation and loss of cytoplasmic integrity; a mechanism that prevents proliferation of dysplastic or mutated cells
Apoptosis
Abnormal increase of basophils in the blood
Basophilia
macrophage derived from PB monocyte and is part of RES; 1-2 histiocytes/macrophages which store iron for Hb synthesis
Erythroblastic island (EI)
Total mass of RBCs circulating in PB and their BM precursors
Erythron
BM process of RBC production
Erythropoiesis
Abnormal decrease in Hb content of RBCs so that they appear pale w/ larger central pallor when stained w/ Wright stain
Hypochromia
Diminished availability of O2to body tissues, usually secondary to decreased lung capacity or decreased O2-carrying capacity of blood
Hypoxia
Productionof erythroid precursor cells that are defective
Ineffective erythropoiesis
Conditions involving ineffective erythropoiesis
- Megaloblastic anemia
- Thalassemia
- Sideroblastic anemia
Describes Wright-stained RBC w/ normal color and normal Hb content w/in average cell Hb concentration w/in reference range; MCHC b/w 32-36%)
Normochromic
Elevated retic count on PB film stained w/ new methylene blue dye or an increase in number of polychromatophilia
Polychromatophilia (reticulocytosis)
Reticulocytosis indicates BM regeneration activity in ____ ____ or ____ ____ ____
Hemolytic anemia; acute blood loss
Degradation of a cell where nucleus shrinks in size and chromatin condenses to solid, structureless mass or masses
Pyknosis
Aging or growing old; RBC loses its deformability and is cleared by the spleen
Senescence
Gray-blue RBC w/ increased diameter; require more than 1 day in PB to lose residual RNA and gain mature-looking reddish cytoplasm
“Shift”/”stress” retic
Stain that colors living tissues or cells
Supravital stain
