OBJECTIVES: At the end of this laboratory session you should be able to identify the cellular and formed elements in peripheral blood and know their functions.
SLIDE FOR THIS LABORATORY: 76.
BLOOD COMPONENTS
Find a region in the blood smear slide where the RBC's are separated (not overlapping). When studying the blood smear slide, pay close attention to nuclear characteristics, staining patterns, and cell diameter (remember that erythrocytes are usually 7-8 µm in diameter). Use the oil immersion lens to identify each cell type.
Slide 76 Peripheral blood smear, Wright's stain.
Identify the following components:
Platelets (small blue-purple clusters)
LEUKOCYTES
Leukocytes (or White Blood Cells) can be divided into two main types: Agranular & Granular. When studying the WBC's, keep in mind the percentages listed below which represent the normal adult leukocyte differential.
| Neutrophils | Eosinophils | Basophils | Lymphocytes | Monocytes |
| 50-70% | 2-4% | 0-1% | 20-40% | 2-9% |
AGRANULAR LEUKOCYTES
Look for fibrillar chromatin in the nucleus and abundant blue cytoplasm. Recall that macrophages arise from monocytes.
Look for clumped chromatin and a thin rim of basophilic cytoplasm.
GRANULAR LEUKOCYTES
These are the most common WBC. Look for multilobed nuclei, individual granules are not distinguishable. The cytoplasm is lightly stained a "sandy" color.
Look for bilobed nuclei, individual granules are distinguishable and eosinophilic (stain intensely red-orange).
These cells are very rare in the blood. Basophils have coarse, basophilic granules that usually obscure the nucleus.