A leukocyte is a white blood cell (leukos = white).
Structure of leukocytes
Leukocytes are produced by the bone marrow and are found in the blood, lymph, lymphoid organs and some connective tissues. Their name comes from centrifugation of blood samples, and the red layer contains the erythrocytes, the transparent layer is plasma and the intermediate white layer contains the leukocytes.
Role of leukocytes
Leukocytes play a very important role in immune defences. There are 4,000 to 11,000 leukocytes in a microlitre (a thousandth of a millilitre) of blood.
Leukocytes contain three main families of cells, depending on their morphology and function:
Blood contains three types of cells: red cells (on the left), platelets (in the centre), and leukocytes (on the right). © DR