Pre-analytical Procedures

Question 1

Autolysis

Answer 1

Self destruction of cells caused by enzymes
Affected by temperature

Question 2

Putrefaction

Answer 2

Destruction of tissues by micro-organisms (bacteria or fungi) - normal flora
Affected by temperature
Large intestine is prone to this rapidly

Question 3

Fixation

Answer 3

First treatment
Prevents autolysis and putrefaction
Ratio of fixative and tissue should he 10:1

Question 4

Procedures in order

Answer 4

Fixation, gross examination, tissue processing. section cutting, staining

Question 5

Tissue processing

Answer 5

Treatments using a sequence of reagents
At the completion, all water in the tissues will have been replaced by molten paraffin wax

Question 6

Embedding

Answer 6

The tissue samples are places in moulds to form wax blocks containing the tissues

Question 7

Section cutting

Answer 7

4-6 micron layer section is required
(1 micron equals one thousandth of a millimeter)

Question 8

Staining

Answer 8

Hematoxylin and Eosin (H+E) is most common stain
Automated

Question 9

Hematoxylin

Answer 9

Dye that stains nuclei blue-grey

Question 10

Eosin

Answer 10

Due that stains many other tissues components in shades of pink-orange

Question 11

Preservation

Answer 11

Temporary and reversible
Doesn’t cause any permanent changes to the tissues
Postpones autolysis and putrefaction