Wednesday, August 15, 2012

Red, White, and .... yes, Blue

In BIO 139 lab this week we are studying the morphology (form, structure) of human blood cells.  We are learning to identify cells based on shape, size, color, nucleus, granules, etc.

There are two main types of cells that we are identifying on the human blood smear slide, Red Blood Cells and White Blood Cells (hence the title of this post!)

A helpful website explaining how to identify some of these cells can be found at a website maintained by the University of Nebraska Omaha.  This Blood Cells website shows photomicrographs of all of the red and while blood cells while pointing out some of the features used to identify each cell type.

Keep in mind that while identifying blood cells, where you look on the slide is very important.  This photo from the Blue Histology website shows that the area of the slide differs because of the way the blood smear is made.  A blood smear is made by placing a drop of blood at one end of the slide, then applying even pressure to spread the blood cells out across the slide.  Ideally you will have an area where the cells are spread out flat enough to see the shape and attributes of the cytoplasm and nucleus.

So, what about the "Blue" in the post title?  That refers to Basophils, which often stain with blue-colored granules.  Basophils often give students fits because they are the most rare cell type on blood smears, and are often hard to find during lab.  Blue Histology has a page with some blood cell information on it that contains several photomicrographs of basophils.  Also, here are a few other photos of basophils.

It is the presence of blue/purple granules in the cytoplasm of the basophil that is characteristic.  One way to tell a basophil from a lymphocyte is to try to view an area of just cytoplasm.  The lymphocyte will have light blue or lavender colored cytoplasm without any granules.  The basophil's cytoplasm will contain granules.

What about functions? gives some general functions for each of the types of white blood cells.  Of course, your lab sheet points out the table in your book that can give you similar information.

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