Anemias may be due to an insufficient number of _____ (e.g., after a loss of blood), an insufficient number of _____ (e.g., when there is insufficient iron in the diet), or an abnormality in the _____ itself (e.g., as in sickle-cell anemia).

3000+ review questions on anatomy and physiology. 

Anatomy refers to the internal and external structures of the body and their physical relationships, whereas physiology refers to the study of the functions of those structures.