Histology is an interesting department; it is certainly part of the lab, but it is very different from the more normally thought of sections such as chemistry and hematology. Histology is concerned with the pathology of tissues, and the bulk of
the work involves the preparation, sectioning, and staining of specimens
for examination by the pathologist. Medical technologists, histotechnologists (who have gone through histotechnology school) and pathologist's assistants work under the supervision of pathologists (or a pathologist in smaller hospitals). Examples of specimens that would be processed by histology include biopsies, removed organs such as appendixes and tonsils, and tumors that have been surgically removed. Autopsy specimens are also handled by histology. The main goal is to preserve the specimen as a whole and then to remove small sections from the specimen for staining and subsequent examination by a pathologist to see if there are any ongoing pathological processes. While it sounds and is very scientific, much of it - especially when it comes to microtomy, which will be discussed more later - is also an art form, including the final product. Below are a few images of stained tissues and after those I will discuss histology in more detail.
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| Thyroid gland stained with a Hematoxylin and Eosin stain at 100X magnification |
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| Skin, also stained with Hematoxylin and Eosin at 100X. The purple layer is the epidermis. |
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| Lung, yet again with Hematoxylin and Eosin at 100X. Open spaces are the alveoli or air sacs. |
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| Colon, Alcian Blue PAS at pH 2.5 and at 400x magnification. The flower-like shapes are various carbohydrates and other macromolecules found in the cells of the lining of the colon that are involved in absorption. |
