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What is Tissue Histology?

Tissue histology is tissue morphology. This means that a histologist will examine all tissue samples grossly. All tissue has a definite “normal” appearance as seen inside and outside its normal environment. This tissue must be described as color, shape, and size before it can be processed for microscopic evaluation. This description (morphology) is part of the tissue histology. The second part is the microscopic description (morphology) of the tissue after it has been stained. The typical stain done on all tissues is the hematoxylin and eosin (H&E). This shows the basic structure of the tissue. All tissue components that are basophilic are stained with eosin and will have a pink hue. All the tissue components that are acidophilic are stained purplish blue with the hematoxylin. These are typically the nuclei that turn blue. This stain allows the identification of a particular tissue type, (muscle, lung, and so on). The examination and description of the microscopic structures constitutes the tissue histology.

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Hematoxylin & Eosin (H&E) Protocol

Safety equipment: Work under a hood with lab coat, gloves, and glasses.

  1. De-paraffin slides in xylene (1) ——————  2 minutes (re-use)
  2. De-paraffin slides in xylene (2)——————- 2 minutes (re-use)
  3. Clear slides in 100% alcohol———————- 2 minutes
  4. Clear slides in 100% alcohol———————- 2 minutes
  5. Hydrate slides in 95% alcohol——————– 2 minutes
  6. Hydrate slides in running water—————–  5 minutes
  7. Stain slides in Harris Hematoxylin————–  10 minutes (re-use)
  8. Rinse slides in running water———————  2 minutes
  9. Differentiate in acid alcohol———————-   1 quick dip (re-use)
  10. Rinse in water————————————–    3 dips
  11. Dip in ammonia water—————————-    15-30 seconds (re-use)
  12. Wash in running tap water———————–    10 minutes
  13. Place in 95% alcohol——————————    2 minutes
  14. Stain in eosin—————————————    1 minute (re-use)
  15. Dehydrate in 95% alcohol————————   1 minute
  16. Dehydrate in 100% alcohol———————-   1 minute
  17. Dehydrate in 100% alcohol———————-   2 minutes
  18. Dehydrate in 100% alcohol———————-   2 minutes
  19. Clear in xylene (3)———————————   2 minutes (re-use)
  20. Clear in xylene (4)———————————   5 minutes (re-use)

Results: Nuclei –Blue   Cytoplasm – Pink     Blood – Red