Which are the most common erythrocytic stages found in normal marrow?

In normal bone marrow, the typical erythrocytic stages present primarily include polychromatophilic normoblasts and orthochromatic normoblasts. These stages reflect the later phases of red blood cell maturation.

Polychromatophilic normoblasts are characterized by their bluish tint due to the presence of ribosomal RNA, which indicates active hemoglobin synthesis. As these cells continue to mature, they transition into orthochromatic normoblasts, which exhibit a more uniform, reddish appearance owing to increased hemoglobin accumulation and a decrease in ribosomal content. At this stage, the cells push out their nuclei, becoming reticulocytes, which are released into the bloodstream and eventually mature into erythrocytes.

Understanding these stages is crucial for recognizing the normal morphology of erythrocytes as they mature in the marrow and tracing the progression of erythropoiesis. Thus, identifying the later stages such as polychromatophilic and orthochromatic normoblasts emphasizes the transition leading to functional red blood cells that are ready to fulfill their roles in oxygen transport.