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21. Hematopoietic tissue. Erythropoiesis
Hematopoietic tissue is composed of reticular fibers and cells, blood vessels, and sinusoids (thin-walled blood cha
Proerythroblast is a large basophilic cell containing a large spherical euchromatic nucleus with prominent nucleoli.
Basophilic erythroblast is a strongly basophilic cell with nucleus that comprises approximately 75 % of its mass. Numerous cytoplasmic polyribosomes, condensed chro-matin, no visible nucleoli, and continued hemoglobin synthesis characteristics of this cell.
Polychromatophilic erythroblast is the last cell in this line undergoes mitotic divisions. Its nucleus comprises approximately 50 % of its mass and contains condensed chroma-tin which appears in a «checkerboard» pattern. The po-lychnsia of the cytoplasm is due to the increased quantity of acidophilic hemoglobin combined with the basophilia of cytoplasmic polyribosomes.
Normoblast (orthochromatophilic erythroblast) is a cell with a small heterochromatic nucleus that comprises approximately 25 % of its mass. It contains acidophilic cytoplasm because the large amount of hemoglobin and degenerating organelles. The pyknotic nucleus, which is no longer capable of division, is extruded from the cell.
Reticulocyte (polychromatophilic erythrocyte) is an immature acidophilic denucleated RBC, which still contains some ribosomes and mitochondria involved in the synthesis of a small quantity of hemoglobin. Approximately 1 % of the circulating RBCs are reticulocytes.
Erythrocyte is the mature acidophilic and denucleated RBC. Erythrocytes remain in the circulation approximately 120 days and are then recycled by the spleen, liver, and bone marrow.
reticular – сетчатый
sinusoids – синусоиды
granulocytes – гранулоциты
agranulocytes – агранулоциты
active – активный
yellow – желтый
glycoprotein – гликопротеин
erythropoietin – эритропоэтин
amount – количество
hemoglobin – гемоглобин
degenerating – дегенерирующие
condensed – сжатый