2.2 Normal blood smear
As you work through this course you will be directed to the virtual microscope to examine lots of different types of samples. You’ll start by looking at a normal blood smear.
Activity 1
Open the virtual microscope [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] in a new browser window or tab. This is helpful so you can operate it while still having access to the instructions you are reading now.
Load Slide 1 (‘Normal blood smear’), which is available from the Week 1 collection in the drop-down menu above the slides and familiarise yourself with the basic controls, including the slide box, the focus and lighting controls, the stage movement controls and the objectives.
When you first access the slides you will find that they are blurry. This mirrors the experience that you would have when you initially looked at a slide under a light microscope, and can be easily remedied by changing the focus settings and the light level.
If you are struggling to focus a given slide, you can click on the spanner icon and click the checkbox for ‘Load slides in focus’, and this will clarify the image. We urge you to try focusing the image manually first though, if possible.
Once you have mastered the microscope’s basic controls, use the legend to identify different cell types in the blood from Slide 1 (‘Normal blood smear’). The predominant cell type is the red blood cell (erythrocyte), which carries oxygen to the tissues, and helps to remove carbon dioxide. Leukocytes, or white blood cells, are involved in immune defence against infection.
There are a variety of different types of leukocytes, all with distinct functions. You will learn more about these cells, and how to identify them, later on in the week. You might like to keep the virtual microscope open as you work through the week.