Key Points. 1  Megaloblasts are large nucleated RBC precursors with noncondensed chromatin. 2  The most common causes of megaloblastic, macrocytic anemia are deficiency or defective utilization of vitamin B12 or folate. 3  Do CBC, RBC indices, reticulocyte count, and peripheral smear.
vein. 1. Any of the blood vessels that carry blood toward the heart. Veins are thin-walled and contain valves that prevent the backflow of blood. All veins except the pulmonary vein (which returns to the heart from the lungs) carry blood having low levels of oxygen. 2.
Of or relating to the veins in the body: venous circulation. 2. Of, relating to, or being the blood in the veins or pulmonary arteries that is usually dark red as a result of low oxygen content. 3. Having numerous veins, as a leaf or the wings of an insect.