EFFECTS OF FIXATION ON TISSUES
Histology is the study of tissues. For these tissues to be studied properly, they are prepared via various processes. These procedures are known as histological techniques. Tissue processing can be performed manually or by the use of an automated tissue processing machine (a “tissue processor”). Tissue processing schedules for enclosed, automatic processors are devised according to species and size / type of tissue. Most Histological techniques have been developed to reserve the structural integrity of the specimens so that it can be viewed microscopically (Schwann, 2008). The aim of good histological technique is to preserve microscopic anatomy of tissue and make them hard, so that very thin section (4 to 5 micron) can be made. After staining, the section should represent the anatomy of the tissue as close to as possible to their structure in life. This is achieved by passing the total as selected part of the tissue through a series of process. For light microscopy, three techniques can be used: theparaffin technique, frozen sections, and semi thin sections. The paraffin technique is the most commonly used (Preece, 2008).Histological techniques involved in preparation of tissues for light microscopy includes: Fixation, Dehydration, Cleaning, Embedding, Cutting, Staining.