TY  - CHAP
M1  - Book, Section
TI  - Structure and Composition of the Erythrocyte
A1  - Narla, Mohandas
A2  - Kaushansky, Kenneth
A2  - Lichtman, Marshall A.
A2  - Prchal, Josef T.
A2  - Levi, Marcel M.
A2  - Press, Oliver W.
A2  - Burns, Linda J.
A2  - Caligiuri, Michael
Y1  - 2015
N1  - 
T2  - Williams Hematology, 9e
AB  - SUMMARYCollectively,  the  erythroid  progenitors,  terminally  differentiating  erythroblasts  (precursors),  and  adult  red  cells  are  termed  the  erythron  to  reinforce  the  idea  that  they  function  as  an  organ.*  The  widely  dispersed  cells  comprising  this  organ  arise  from  pluripotential  hematopoietic  stem  cells.  Following  commitment  to  the  erythroid  lineage  (unipotential  progenitor),  further  maturation  gives  rise  to  the  erythroid  progenitors,  burst-forming  unit–erythroid  and,  subsequently,  colony-forming  unit–erythroid  (CFU-E),  that  can  be  identified  by  their  development  into  representative  clonal  colonies  of  red  cells  in  vitro.  The  CFU-E  then  undergoes  terminal  differentiation,  progressing  through  four  to  five  morphologic  stages,  each  having  characteristic  light  microscopic  and  ultrastructural  features.  During  terminal  erythroid  differentiation  there  is  an  increasing  amount  of  hemoglobin  synthesis  accompanied  by  nuclear  chromatin  condensation  and  at  the  final  stage  of  differentiation  there  is  nuclear  extrusion  to  generate  an  anucleate  polychromatophilic  macrocyte  (reticulocyte  with  supravital  staining).  The  human  polychromatophilic  macrocyte  (reticulocyte)  matures  over  2  to  3  days,  first  in  the  marrow  and  then  in  circulation  into  the  discoid  erythrocyte.  During  reticulocyte  maturation,  cytoplasmic  inclusions  including  residual  mitochondria  and  ribosomes  are  degraded  and  the  reticulocyte  loses  surface  area  to  achieve  the  mean  cell  volume  and  surface  area  of  a  discoidal  erythrocyte.  Mature  erythrocytes  are  approximately  7  to  8  μm  in  diameter  and  undergo  extensive  deformation  to  pass  through  3-μm  diameter  capillaries  and  the  1-μm  wide  and  0.5-μm  thick  endothelial  slits  in  the  red  pulp  of  the  spleen.  The  ability  of  the  red  cell  to  undergo  extensive  reversible  deformation  is  essential  for  both  its  function  and  its  survival.  Red  cell  deformability  is  a  function  of  its  geometry,  the  viscosity  of  the  cytoplasm,  largely  determined  by  the  concentration  of  hemoglobin.  Decreased  deformability  is  a  feature  of  red  cells  in  various  pathological  states.  The  erythrocyte  is  unique  among  eukaryotic  cells  in  that  its  principal  physical  structure  is  its  cell  membrane,  which  encloses  a  concentrated  hemoglobin  solution.  Thus,  all  of  the  structural  properties  of  this  cell  are  in  one  way  or  another  linked  to  the  cell  membrane.  In  contrast  to  other  cells,  the  erythrocyte  has  no  cytoplasmic  structures  or  organelles.  Only,  red  cells  and  platelets  do  not  have  a  nucleus.  
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/19
UR  - accessmedicine.mhmedical.com/content.aspx?aid=1121091284
ER  -