Pathology - Intro

Question 1

Define Pathology, Histology and Histopathology

Answer 1

Pathology - study of disease
Histology - study of cells and tissues by microscopy
Histopathology - study of diseased cells and tissues by microscopy

Question 2

Define Epidemiology and Aetiology

Answer 2

epidemiology - population distribution of disease

aetiology - cause of the disease

Question 3

Define Pathogenesis?

Answer 3

how the disease develops

Question 4

define prognosis

Answer 4

the anticipated course of the disease

Question 5

4 Steps of Treatment from the start

Answer 5

make diagnosis
determine prognosis
plan treatment
confirm response to treatment

Question 6

10 Steps of Histological Process Examination

Answer 6

1. tissue
2. fixation
3. cut up the section
4. process the tissue
5. cutting and mounting
6. staining
7. scanning
8. microscopy
9. diagnosis
10. prognosis prediction

Question 7

What is tissue fixation?

Answer 7

preservation of tissues

Question 8

2 ways in which tissues decay

Answer 8

• autolysis - intrinsic autolytic enzyme action
• putrefaction - bact. contamination

Question 9

4 Different Fixatives, how do they work?

Answer 9

Aldehyde - form protein covalent cross-links
Alcohol - denature proteins = aggregation
Oxidising = protein cross links
Freezing

Question 10

2 Aldehyde Fixatives.

Answer 10

Formalin
Glutaraldehyde

Question 11

Which is the most common Fixative?

Answer 11

Formalin - formaldehyde solution

Question 12

why is formalin the most common fixative? (3)

Answer 12

• protein covalent cross links
• good penetration and mech. strength
• good tissue morphology preservation

Question 13

one negative of formalin

Answer 13

poor nucleic acid preservation (DNARNA)

Question 14

how long is formalin effective for?

Answer 14

24-48 hrs

Question 15

how do you cut thin sections of tissue in tissue processing?

Answer 15

place it in wax

Question 16

what 2 properties must the tissue have when it is cut thin?

Answer 16

stiff and resistant to tearing

Question 17

why cant tissue just be dropped into water?

Answer 17

wax = hydrophobic
water = hydrophilic

Question 18

how do you remove water from the tissue and embed into wax? (3)

Answer 18

dehydration by alcohol
replace alcohol with xylene - cleans
replace xylene with paraffin wax

Question 19

what does FFPE stand for?

Answer 19

formalin fixed paraffin embedded tissue

Question 20

What is the most common stain?

Answer 20

Haematoxylin and Eosin Stain

Question 21

Describe Haematoxylin and Eosin Stain.

Answer 21

haemotoxylin
- basic dye
- stains acid structure purple
- DNA = purple

Eosin
- acidic dye
- stains basic structures pink
- proteins = pink

Question 22

is H&E stain specific?

Answer 22

no
-only specific to acid and base structures

Question 23

what is immunohistochemistry?

Answer 23

the process of identifying specific antigens by using the principles of antibody binding

Question 24

define metaplasia

Answer 24

a change in which one differentiated cell type is replaced by another cell type

Question 25

define pathogenesis

Answer 25

the exact mechanism that causes the disease

Question 26

define infarction

Answer 26

tissue necrosis as a consequence of ischaemia