Preparing Tissue For Microscopy

Question 1

What are the 4 stages of preparing tissue for microscopy?

Answer 1

1. Fixation
2. Tissue support
3. Cutting
4. Staining

Question 2

What is the process of fixation and how is it done?

Answer 2

WHAT:
Preserving tissue in life-like condition by inhibiting enzyme activity to prevent autolysation

HOW:
Dehydration
Cooling and freezing (can distort the tissue sample due to ice crystals)
Chemical fixatives i.e. Formaldehyde or Glutaraldehyde or Alchohols

Question 3

How is paraffin wax used in tissue support? What must be done before this process can occur?

Answer 3

Paraffin replaces cellular compartments which contained water to provide uniform density so the tissue can be cut

Tissue needs to be dehydrated with water because paraffin is immiscible with water

Question 4

What equipment is used to cut a sample and how thick are the slices?

Answer 4

Microtome

4 micrometres

Question 5

What are the charges, targets and staining colours of H+E stains?

Answer 5

Haematoxylin
+ve
Nucleus
Blue/purple

Eosin
-ve
Cytoplasm + ECM (attract to +ve proteins)
Pink