Histopathology

Question 1

What is used in medical histopathology?

Answer 1

Any material used in diagnostic purpose; e.g. Appendix, Colon, Body Fluids, etc…

Question 2

How is human disease histologically identified?

Answer 2

Identifying abnormailities within a histopathological sample is done via testing biospys, fluid samples, etc…

Question 3

How might histopatholigical samples be dealt with?

Answer 3

1. Preserve; against autolysis & putrefaction
2. Select; what will be useful in investigation
3. Identify; what is wrong

Question 4

How is a sample fixed?

Answer 4

Samples are typically fixed using formalin

Question 5

What does fixation do?

Answer 5

Preserves tissues and organic matter in a life-like condition to prevent decay.

Question 6

Define; Autolysis & Putrefaction?

Answer 6

Autolysis; enzymatic digestion of cells by the action of its own enzymes.
Putrefaction; process of decay in a body.

Question 7

What is formaldehyde?

Answer 7

Formaldehyde is carcinogenic to the body but useful in histopathology; it holds proteins in shape and denatures them preventing decay.

Question 8

What is formalin?

Answer 8

Formalin is a 10% neutral buffer. Its made from water and formaldehyde and used to fix samples.

Question 9

Outline the process of specimen dissection.

Answer 9

1. Area of interest; area of suspicion (e.g. tumor)
2. Clearance margins; margins cut around a tumor to ensure no cancerous cells are present
3. Depth; depth of invasion of a cancer, indicating the progression of the cancer
4. Pleomorphic tumor; differntiating parts of cancerous tumors(not uniform)
5. Normal tissue; base tissuing outlining the healthy

Question 10

How are pathological speciemens processed?

Answer 10

Samples are cast into paraffin wax.

Question 11

What dyes are used in basic histological stains?

Answer 11

Haematoxylin & Eosin Y

Question 12

What does Haematoxylin stain?

Answer 12

Stains cell nucleus blue

Question 13

What does Eosin Y stain?

Answer 13

Stains eosinphilic tissue pink

Question 14

Name 3 histopatholgical sample special stains used in morphology.

Answer 14

Collagen; stained pink.
Hepatitis; Orcein stain is used to pick up the hepatitis B surface antigens.
Haemosiderin; Pearl stains are used here to pick up any traces of iron.

Question 15

What are the 3 stains for Micro-organisms?

Answer 15

Gram
Ziehl-Neelson
Grocott

Question 16

What does a Gram stain do?

Answer 16

Only determines whether bacterium is present(purple) or absent(pink).

Question 17

What does a Ziehl-Neelson stain do?

Answer 17

Identifies myobacterium present within sample; blue = normal, red = infection

Question 18

What does a Grocott stain do?

Answer 18

Identifies presence of fungi; fungal infection

Question 19

Why are samples cast into paraffin wax?

Answer 19

In order to obtain thingly sliced sections of samples for observation.

Question 20

Why is the processing of histipathological samples reversed?

Answer 20

When attempting to stain a sample cast in paraffin wax the water-based stain will not work properly since wax is made of oil. The reverse is done to extract the oil.