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.
Wiktionary (0.00 / 0 votes) Rate this definition: vein (Noun). A blood vessel that transports blood from the capillaries back to the heart. vein (Noun). (used in plural veins) The entrails of a shrimp. vein (Noun). In leaves, a thickened portion of the leaf containing the vascular bundle. vein (Noun).
Veins are the blood vessels which carry the blood from peripheral tissues towards heart. They carry the deoxygenated blood, which is bluish in color and for the same reason veins appear blue. Veins are thin-walled, being thinner than the arteries.