Why, in the case of blood, does one speak of formed elements rather than the cellular component?
In the case of blood, formed element is a term referring to a struture that has a definite shape. The erythrocytes (red) and leukocytes (white) are formed elements. In addition, the platelets are considered formed elements because they are pieces of cytoplasm (each surrounded by a plasma membrane) rather than whole cells, we cannot refer to the cellular component of the blood if we include them.