Figure 1-3. Leukocytes-nongranular.
c. Thrombocytes. Thrombocytes are commonly called "platelets." They are
detached irregular shaped fragments of their precursor cells (which are found in the
bone marrow). These precursor cells are giants in size compared to the other blood
cells. The platelets live for only 3 to 5 days. The platelets contain different clotting
factors and other components that are either known or presumed to participate in the
clotting process. They clump together to form a plug in the initial phase of controlling
bleeding. This process is speeded up by thrombin, an enzyme involved in blood
clotting. A deficiency in platelets causes a tendency to bleed. The platelets possess
ameboid movements. This property is very necessary for the clotting process. (See
Figure 1-4. Platelets.