Final answer:
The bone marrow morphology of megaloblastic anemia is marked by abnormal maturation of erythroblasts leading to macrocytic, oval-shaped red blood cells, often due to vitamin B12 or folic acid deficiency.
Step-by-step explanation:
The bone marrow morphology of megaloblastic anemia is characterized by distinctive changes in the development of blood cells. In megaloblastic anemia, red blood cell precursors (erythroid progenitors) exhibit abnormal maturation of the nucleus compared to the cytoplasm, due to impaired DNA synthesis. This impeded maturation is typically induced by deficiencies in vitamin B12 or folic acid. The erythroblasts (red blood cell precursors) in the bone marrow become unusually large with nuclear-cytoplasmic asynchrony, leading to the term 'megaloblasts.' These changes can be observed on a stained blood smear slide, evidenced by macrocytic and oval-shaped red blood cells. A Wright-Giemsa stained blood smear is often used to examine these changes under a microscope.
On a morphological level, anemias are categorized based on red blood cell size, described as microcytic, normocytic, and macrocytic. In megaloblastic anemia, which falls under the macrocytic class, the mean corpuscle volume (MCV) is elevated, indicating larger-than-normal red blood cells.