 Hematologic cells and their functions. In this learning object, we will identify normal blood cells and their functions. This will include the identification of red blood cells, five types of white blood cells, and platelets. Neutrophil. Medium-sized, mature white blood cell with a three-to-five lobed nucleus that stains purple. The cytoplasm contains small, lilac staining granules. Neutrophil fights infections by internalizing microorganisms for destruction and is increased in people with bacterial infections. Eosinophil is a white blood cell that contains large red-orange granules in the cytoplasm and has a blue segmented nucleus. Attempts to suppress inflammatory tissue reactions and is increased in people with parasitic infections and allergies. Basophil. A white blood cell with large deep, bluish-purple granules in the cytoplasm has a blue segmented nucleus. Basophil plays a role in acute and delayed allergic reactions. Basophil is the least numerous of the white blood cells. Monocyte. Monocytes are the largest peripheral white blood cells. They are 12 to 24 microns in diameter and have a convoluted or indented nucleus. They have a blue-gray cytoplasm that may contain vacuoles. Monocytes are the most important phagocytic cell. Lymphocyte. Lymphocytes are the smallest peripheral white blood cell. They have a round blue nucleus with light blue cytoplasm and are 7 to 15 microns in diameter. A lymphocyte regulates the immune system and plays a role in antibody production. Erythrocyte. An erythrocyte is a red blood cell with a biconcave disc 6 to 8 microns in diameter and stains pinkish red. An erythrocyte transports oxygen and carbon dioxide. Platelet. A platelet is a tiny blue cell fragment that is 1.5 to 4 microns in diameter and has no nucleus. A platelet plays a role in blood coagulation. You have completed hematologic cells and their functions.