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6.2 Practice problems

  1. A researcher purified some platelets from human blood. She then added an aliquot of this suspension to a haemocytometer (Figure 6.7). Estimate the platelet concentration (cells ml1) of her suspension. The haemocytometer has a depth of 0.1 mm.
  2. From your knowledge of erythrocytes, estimate the size (in µm) of the leukocyte in the micrograph (Figure 6.8). What type of leukocyte do you think it is?

 

An actual micrograph showing one of the outer corner squares from a haemocytometer containing purified human platelets.
Figure 6.7: A diagram showing one of the outer corner squares from a haemocytometer containing purified human platelets. The dimensions of the main square are 0.2 mm x 0.2 mm with a depth of 0.1 mm.

 

A photomicrograph of an unknown leukocyte showing a lot of granulation. The leukocyte is around twice the diameter of neighbouring erythrocytes.
Figure 6.8: Unknown leukocyte (‘Mast cell leukemia’ by Ayman Qasrawi from Wikimedia Commons used under CC0)

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