Figure 1.

Normal platelets obtained from the peripheral blood. (A) Thin section of the epoxy-embedded platelets demonstrates a number of various organelles. Dense granules are not readily seen in the sections of platelets as not all will be within the plane of the section; the majority of the “dark” bodies are alpha granules. (B) A whole mounted and air-dried platelet includes all the granules within the cell. Dense granules appear opaque black due to the calcium content of these organelles that vary in both size and density. Many obscure gray shadows may be seen; these represent the alpha granules that are not electron dense and are in the number range of 50–80 per platelet.