Cutts Report

2 Found helpful • 17 Pages • Essays / Projects • Year: Pre-2021

Histopathology involves cutting and identification of various specimens where there histological features can be stained a particular way and viewed under a microscope. Rats are a useful animal used in histology where they can be used to benefit our leaning. The anatomy of a rat is similar in composition to us humans where we have the same circulatory system and share similar muscles and similar skeletal structure (3). Using rat’s allows us expand our knowledge and learn particular structures and functioning’s of rats and most importantly relate it to humans since similar structures are shared. In this practical precise measures are put into place in order to dissect a rat and remove valuable organs and bones for assistance in research and identifying cell structures. The valuable tissues removed from the rat included the liver, trachea and oesophagus, duodenum, lung, bone and kidney. Careful measures are taken in the dissection to avouch damaging tissues, once they are removed they are placed in fixative and are prepared for embedding. Embedding requires a high level of precision order for accurate placing of the rat sections in the wax and that they are in the correct orientation. Once set in paraffin wax, these sections are then required to be cut with a microtome at 4 microns (2). This allows the tissues to be into thin even sections, adhere to the slide and allow an adequate amount of the specimen on the slide. Implications can arise during the processing stage which need to be avoided as it can diminish the quality of the sections and make the examination difficult in identifying cellular structures of the specimens. Once tissues have adhered on the slides they are then further processed with a particular stain, there are various stains available that allow different components and structures to be seen. A common stain used is the haematoxylin and eosin (H&E) stain where it was used to stain the rat’s lung, liver, duodenum, trachea and bone. H&E done regressively which involves the overstaining of haematoxylin and uses Harris hematoxylin. Haematoxylin stain nuclear components such as nucleus and chromatin, whilst eosin stains the cytoplasm of cells in different shades of pink and red (1). Other stains include a perls stain where the pigments stain blue give a positive reaction given by hemosiderin. Halls stain where pigments are stained green as a positive reaction given by bilirubin. An AB PAS stain used to identify acidic and neutral mucins, as PAS D stain to distinguish glycogen. A mason’s trichrome stain to stain collagen blue and muscles red. Once the specimens have been stained they are then ready to be looked at under the microscope where certain cell components are stained particular colours makes the identification of histological components much easier. (2) The overall aim of this exercise is to dissect a rat and gather various specimen samples of the rats o be embed, stain with the use of a variety o different stains and then examine under a microscop

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