Intro to histo

Question 1

Define histology

Answer 1

Histology is the microscopic study of normal cells and tissues

Question 2

Key difference between light and electron microscope

Answer 2

Light
- lower resolution of 0.2um
- coloured images, staining available
- better for looking at overall structure of cell
- commonly used in histopathology

Electron
- higher resolution of 1nm
- ultrastructure of cell
- better for organelles

Question 3

Stages to collect and prepare tissues for histological examination

Answer 3

Collection , fixation, dehydration, embedding, sectioning, staining

Question 4

Commonly used staining procedures

Answer 4

Haematoxylin and Eosin
Periodic acid Schiff
Alcian blue
Immunohistochemistry
Masson trichrome

Question 5

H&E colours

Answer 5

H is a basic dye that stains nuclei acids (ie acidic stuff) blue/purple
E is an acidic dye that stains cytoplasm and other basic structures pink/red

Question 6

Alcian blue

Answer 6

Stains mucins blue

Question 7

PAS

Answer 7

stains complex carbs magenta

Question 8

Masson trichrome stains

Answer 8

Green collagen
Cytoplasm red
Nucelci acids blue

Question 9

What is fixation

Answer 9

Use formaldehyde to terminate chemical processes, prevent tissue decomposition
Glutaraldehyde in EM

Question 10

Dehydration

Answer 10

Use graded alcohols to remove water
Graded to prevent lysis and distortion

Question 11

Embedding

Answer 11

Paraffin wax but need to use xylene first

Question 12

Sectioning

Answer 12

Use microtome

Question 13

Staining

Answer 13

Rehydrate first because most stains not compatible with paraffin wax

Question 14

Types of collection

Answer 14

Punch/incision
Endoscopic
Needle

Question 15

What is a basic dye

Answer 15

Haematoxylin. It stains acidic structures