Introduction To Cellular Pathology Flashcards
What are the 3 steps that we need prepare a microscopy
- Fixation
- Cutting a thin enoguht section for light tranmission
- Staining
Why do we need to fix a tissue
Living celels have enyzmes tbat digest tissue and need oxygen to survive
When we take that away dying cell release enzymes which kill its own cell (autolyse)
To prevent this we fix the tissue
What are the 3 methods of fixation
- Dehydration
- Cooling and freezing
- Chemical fixatives
What is the method dehydration like
- You extract the water form the cell
2. Wihtout water the enzymes activity stops
How can you dehydrate a tissue
- air dry
Or - appyl salt to extract the water
How does colling and freezing fix tissue
This slows down the metabolic acivity of the cell
How does chemical fixation work
- You use chemical such as formaldehyde and glutaraldehyde alcohol
- Chemical stios enzymes from working by forming bonds between adjacent proteins
If you cut a fresh or fixed tissue what would happen to it
Crumble
To stop a tissue from crumbling when cutting it into thin section what is needed
Tissue support
How do we support the tissue
- We use paraffin wax
- First aply ehtonol to clear water out of cells
- Then use xylene to clear the alcohol
- Apply the paraffin wax which will be miscible (mixes)
If we are cutting a bone into a thin section what do we do to make it soft
Decalcify it using acid
What is the most common stain used to visualise cells under a microscope
Haemtoxylin and eosin (H&E) stain
What colour does haematoxylin show
Purple
What colour does eosin show
Pink
What structure does haemotoxylin show
Nuclues
