Locate the following structures on blood slides, using display materials for assistance
and note the information below. Draw the structures and record definitions. Refer to
your text for definitions.
Erythrocytes: (red blood cells) range from 4.5-5 million cells/mm3. (note: 1 mm3 = 1 µl)
The cells are small, reddish, and have no nucleus. Define anemia and explain at least
three potential causes. Define polycythemia and explain two causes.
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Platelets: these small, purple-stained cell fragments range from 250,000-500,000/mm3.
They are important in the clotting process.
Leukocytes: (white blood cells) range from 4000-11,000 cells/mm3. The basic function
of these cells is protective, and they can move in and out of blood vessels (diapedesis)
and wander through body tissues by amoeboid motion. Find a neutrophil, lymphocyte
and monocyte. If possible, also find an eosinophil and a basophil. There are several
characteristics that can be used to tell WBCs apart, but the best ones are size of the cell
(relative to a RBC) and color of the cytoplasm.
If the size of the cell is:
• similar to RBC or just barely larger than RBC = lymphocyte
• much larger than RBC = not a lymphocyte
If the color of the cytoplasm is:
• Pink or lavender = neutrophil
• Blue or grey = lymphocyte OR monocyte
Granulocytes are larger than RBCs and have lobed nuclei and granules in their
cytoplasm.
Neutrophils: 40-70% of WBCs, 3-7 lobed nucleus, pale lilac or pink
cytoplasm contains very fine granules which are difficult to see. They are
active phagocytes and fight bacterial invasions (important in inflammatory
response) as well as cleaning up debris.
Eosinophils: 1-4% of WBCs, figure 8 or bilobed nucleus, large red/orange
cytoplasmic granules. Important in ending allergic reactions (phagocytize
antibody-bound allergens) and fighting parasitic worms.
Basophils: less than 1% of WBCs, nucleus often U or S shaped with
indentations, large dark purple cytoplasmic granules. Mediate
inflammatory response (release histamine and other molecules) during allergic
responses and parasitic infections.
Agranulocytes have no observable granules and nuclei are usually roughly spherical.
Lymphocytes: 20-40% of WBCs, about the size of a RBC, dark blue or purple
nucleus, sparse gray/blue cytoplasm. Important role in immune system.
Monocytes: 4-8% of WBCs, largest of the WBCs, dark blue nucleus,
abundant gray/blue cytoplasm. They are active phagocytes and considered
important in long-term clean up.
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