Blood Cells Laboratory Exercise 38

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Rudolph Bryant
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1 Blood Cells Laboratory Exercise 38 Background Blood is a type of connective tissue whose cells are suspended in a liquid intercellular substance. These cells are mainly formed in red bone marrow, and they include red blood cells (erythrocytes), white blood cells (leukocytes), and some cellular fragments called platelets (thrombocytes). Red blood cells transport gases between the body cells and the lungs, white blood cells defend the body against infections, and platelets play an important role in stoppage of bleeding (hemostasis). Materials Needed Textbook Compound light microscope Prepared microscope slides of human blood (Wright s stain) Colored pencils Purpose of the Exercise Review the characteristics of blood cells, examine them microscopically, and perform a differential white blood cell count. Procedure 1. Complete Part A. 2. Refer to figure 38.1 as an aid in identifying the various types of blood cells. Use the prepared slide of blood and locate each of the following: red blood cell, neutrophil, eosinophil, basophil, monocyte, lymphocyte, platelet. 3. In Part B, prepare sketches of single blood cells to illustrate each type. Pay particular attention to relative size, nuclear shape, and color of granules (if present) in the cytoplasm. 4. A differential white blood cell count is performed to determine the percentage of each of the various types of white blood cells present in a blood sample. The test is useful because the relative proportions of white blood cells may change in particular diseases. Neutrophils, for example, usually increase during bacterial infections, whereas eosinophils may increase during certain parasitic infections and allergic reactions. 1

2 To make a differential white blood cell count, follow these steps: a. Using high-power magnification, focus on the cells at one end of a prepared blood slide where the cells are well distributed. b. Slowly move the blood slide back and forth, following a path that avoids passing over the same cells twice. c. Each time you encounter a white blood cell, identify its type and record it on the table in Part C. d. Continue searching for and identifying white blood cells until you have recorded 100 cells in the data table. Because percent means parts of 100, for each type of white blood cell, the total number observed is equal to its percentage in the blood sample. 5. Complete Part C. Figure 38.1 Illustrations of the various types of blood cells. Figure 38.2 A table showing the normal values for a differential white blood cell count. Cell Type Normal Value (percent) Neutrophil Lymphocyte Monocyte 3-9 Eosinophil 1-3 Basophil <1 2

3 Part A Complete the following statements. 1. Mature red blood cells are also called. 2. The shape of a red blood cell can be described as a disc. 3. The function of red blood cells is. 4. is the oxygen-carrying substance in a red blood cell. 5. Red blood cells with high oxygen concentrations are bright red because of the presence of. 6. Red blood cells will not reproduce because they lack when they are mature. 7. White blood cells are also called. 8. White blood cells with granular cytoplasm are called. 9. White blood cells lacking granular cytoplasm are called. 10. Polymorphonuclear leukocyte is another name for a with a segmented nucleus. 11. Normally, the most numerous white blood cells are. 12. White blood cells whose cytoplasmic granules stain red in acid stain are called. 13. are normally the least abundant of the white blood cells. 14. are the largest of the white blood cells. 15. are small agranulocytes that have relatively large, round nuclei with thin rims of cytoplasm. 16. In red bone marrow, platelets develop from stem cells called. 17. Upon an injury, platelets adhere to found in connective tissue. 18. In the presence of damaged blood vessels, platelets release a substance called, which causes smooth muscle contraction. 3

4 Part B Sketch a single blood cell of each type in the following spaces. Use colored pencils to represent the stained colors of the cells. Label any features that can be identified. Erythrocyte Neutrophil Lymphocyte Monocyte 4

5 Eosinophil Basophil Thrombocyte 5

6 Part C Differential White Blood Cell Count Data Table. As you identify white blood cells, record them on the table by using a tally system, such as IIII II. Place tally marks in the Number Observed column, and total each of the five WBCs when the differential count is completed. Obtain a total of all five WBCs counted to determine the percent of each WBC type. Type of WBC Number Observed Total Percent Neutrophil Lymphocyte Monocyte Eosinophil Basophil Total of column How do the results of your differential white blood cell count compare with the normal values listed in figure 38.2? Critical Thinking Application What is the difference between a differential white blood cell count and a total white blood cell count? 6

Exercise 9: Blood. Readings: Silverthorn 5 th ed, 547 558, 804 805; 6 th ed, 545 557, 825 826.

Exercise 9: Blood. Readings: Silverthorn 5 th ed, 547 558, 804 805; 6 th ed, 545 557, 825 826. Exercise 9: Blood Readings: Silverthorn 5 th ed, 547 558, 804 805; 6 th ed, 545 557, 825 826. Blood Typing The membranes of human red blood cells (RBCs) contain a variety of cell surface proteins called