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Flashcards in Introduction Deck (32)
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1

What is tissue biology/histology?

Study of the morphological features of normal tissues and the relationship to tissue function

2

What is morphology?

The form and structure of organisms

3

Why must we fix tissue?

Because unfixed tissue will degrade by autolysis

4

What is autolysis?

Self digestion - the destruction of a cell through the action of its own enzymes

5

Give two examples of fixatives?

Alcohol based of formalin

6

How does an alcohol based fixative work?

By denaturing the proteins

7

How does formalin work and what is the active agent?

The active agent is formaldehyde (37%) - it works by cross-linking proteins

8

Why are tissue blocks passed through graded alcohols in the tissue fixation process?

To dehydrate the tissue

9

What are the tissues embedded into?

Paraffin wax

10

What type of block is the tissue embedded into?

A paraffin blox

11

What machine cuts sections from the paraffin block?

A microtome

12

What size are the tissues cut into from the paraffin block?

0.004mm

13

After the sectioning procedure what is done?

The tissue sections are mounted onto a glass slide

14

When the tissue sections are on the glass sides what is done next?

The glass slide sections are stained

15

What does the processing and embedding stage of the preparation process provide you with?

It leaves you with tissues embedded into molten wax

16

If you could describe the preparation of a tissue on a glass side in five stages what would they be?

Processing and embedding
Embedding tissue into paraffin block
Sectioning
Mounted onto a glass slide
Section stained

17

Give an example of a basic dye

Haematoxylin

18

Give an example of an acidic dye

Eosin

19

What are the two main dyes used in tissue fixation?

Haematoxylin and eosin

20

What charge do basic dyes have?

positive

21

What charge do acidic dyes have

negative

22

What charge do basic dyes bind to and why?

Basic dyes are positively charged so they bind to negatively charged tissue components

23

What charge do acidic dyes bind to and why?

Acidic dyes are negatively charged so they bind to positively charged tissue components

24

What is basophilia?

Binding of a basic due to a tissue component

25

What colour does haematoxylin stain?

Blue

26

What components would the basic dye haematoxylin bind to?

Nuclear chromatin, cytoplasmic rna and certain extracellular matrix proteins such as cartilage

27

What is acidophilia?

The binding of an acidic dye with tissue

28

What colour does eosin stain?

pink

29

What components would the acidic dye eosin bind to?

Cytoplasmic proteins including cytoskeleton, intracellular membranes, most extracellular protein fibers, e.g. collagen

30

How many times does a light microscope magnify?

1000x