Looking at blood cells

You may be given some prepared slides of blood to examine with the microscope.

Many types of blood cell are 10 μm in size or less. You will need high power to examine them.

Diagram showing red and white blood cells. There are more red than white

The slides will have been stained to show the cells, and cell features. The micrograph shows many red blood cells and three white blood cells.

An example of a commonly-used stain is Giemsa stain. It aids identification by staining:

Red blood cellsPink
PlateletsPale pink
White blood cell cytoplasmPale blue
White blood cell nucleiMagenta

Looking at cells in a blood smear

Aim

To use a light microscope to see blood cells in a smear.

Method

  • Place a drop of blood onto a microscope slide.
  • Add a drop of stain to the blood to make the cells easier to see.
  • Carefully place a coverslip over the drop of blood. Sliding it slightly along the microscope slide will spread out the blood cells making them easier to see.
  • Follow the instructions below to see the blood cells on a light microscope.
Investigating cells with a light microscope

Rotate the objective lenses so that the low power, eg ×10, is in line with the stage.

Investigating cells with a light microscope

Turn the coarse focus so that the stage is as close to the objective lens as possible.

You should not look through the microscope to do this.

Investigating cells with a light microscope

Place the microscope slide on the stage.

Line it up so that the specimen – if you can see it – is in the centre of the stage, where the light passes through.

Investigating cells with a light microscope

Focus the slide towards you by turning the coarse focus adjustment.

Health and safety

curriculum-key-fact
The exchange of any bodily fluids between people can result in the transfer of disease. Relevant risk assessments must be completed and approved before this practical.

Results

Blood cells stained with Wright's solution

You are likely to see an image like this. Here you can see larger white blood cells and smaller red blood cells. The cells have been stained using Wright's solution stain.

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