Staging Microscopy Flashcards
What is the purpose of fixation in tissue processing?
To preserve fresh tissue
Fixation depends on the size of the tissue and the type of fixative used. Most commonly, formaldehyde is used
What are the steps involved in processing tissue?
Goes through increasing strengths of alcohol solution:
* 70%
* 85%
* 100%
This is done to remove water and prevent shrinkage.
What is the role of paraffin wax in tissue processing after dehydration?
Paraffin wax is not soluble in alcohol
After dehydration, tissue is placed in a solvent that works with alcohol and paraffin wax, such as Histolene.
Describe the embedding process in tissue preparation.
Tissue is removed and placed in a metal mould filled with molten wax, then extra wax is added, and the mould is cooled
This creates a paraffin block.
What equipment is used for section cutting in tissue preparation?
A rotary micro-turn
The knife is clamped into the micro-turn and eased towards the block.
What happens to the sections after cutting?
Ribbons are produced - folds in the ribbon are removed in a warm water bath. They are collected, placed on a microscope slide, and dried in an oven overnight
Need to then dissolve wax with a clearing agent.
What is the purpose of staining in tissue preparation?
To enhance visibility of cellular structures
H+E stains are commonly used.
What do H and E stain in H+E staining?
H (hematoxylin) = nuclei blue-black, E (eosin) = cytoplasm and intracellular components pink
Overstraining of H is removed using a 1% hydrochloric acid solution.
What is the final step in making a tissue section permanent?
Dehydrate in absolute alcohol then cleared, followed by adding adhesive PIX and covering with a glass slip
PIX hardens when placed in an oven at 40 degrees overnight.
Fill in the blank: Without processing tissue, it is not _______.
permanent
True or False: The embedding process involves cooling the mould after adding molten wax.
True
