Lecure 2 - Microscopes, Tissue Prep, and Staining Flashcards
1
Q
What are the steps of tissue fixing and embedding?
A
- fixing
- dehydration
- clearing (removal of alcohol)
- embedding
2
Q
What does tissue fixing do?
A
- prevents further deterioration
- hardens tissue
- distorts specimen
3
Q
What is the most common fixative?
What does it do?
What is its downside?
A
- formalin is the most common, no good if fine cytological detail is desired
- reacts with amino acids to stabilize tissues
- not good for fine cytological detail
4
Q
What are acidic fixatives used for?
A
- fixing chromatin, nucleoli, and spindle fibers (basic cell components)
- Carnoy’s fluid, Zenker’s fluid, and Bouin’s fluid
5
Q
What are basic fixatives used for?
A
-fixing mitochondrial components
6
Q
What is tissue dehydrating?
A
-removal water by going through successively increasing strengths of ethanol
7
Q
What is tissue clearing?
A
-replacing alcohol with an agent such as xylene or cedar oil
8
Q
What is tissue embedding?
A
-placing in several paraffin baths
9
Q
What is the most common stain?
A
-H&E (hematoxylin and eosin)
10
Q
What are PAS positive substances?
A
- polysaccharides
- glycosaminoglycans
- proteoglycans
- glycoproteins
- glycolipids
11
Q
What are metachromatic stains?
A
- stains that changes color
- ex. toluidine blue
