사람태아 간의 적혈구형성세포의 미세구조 변화

Abstract

The ultrastructural changes of erythropoietic cells were studied according to the maturation stages in human fetal liver. The erythropoietic cells were observed in hepatic plates and the most undifferentiated erythropoietic cell was proerythroblast. The cytoplasm of the cell had several mitochondria, RERs and low electron density. The oval nucleus had prominent nucleolus and slight peripheral heterochromatin along the inner nuclear membrane. The size of cells and nuclei became smaller with clumping of chromatin in the course of successive maturation stage, i.e. basophilic, polychromatophilic, and eosinophilic erythroblasts. The nucleus was enucleated from full-mature eosinophilic erythroblast and phagocytized by Kupffer cell lining sinusoidal wall. The intracellular organelles underwent, degeneration and the size became smaller with maturation. But the electron density of cytoplasm increased due to accumulation of hemoglobin. The erythropoietic cells appeared in cell mass composed of 5-10 cells, and made bleb-like cytoplasmic processes. In addition, the cells in granulocytopoiesis and megakaryocytopoiesis were found. In summary, it is suggested that the erythropoiesis formed in hepatic plates is initiated by hemopoietc stem cell originated from mesoderm of yolk sac.