Module 1-3 Flashcards

1
Q

Name three chromophores

A

Quinoid, Azo, and Nitro groups

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2
Q

What is an amphoteric dye?

A

A dye that can be acidic or basic depending on the pH of the solution it is in

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3
Q

Natural stain that is used as a nuclear stain

A

Hematoxylin

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4
Q

Common basic auxochrome

A

Amino group

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5
Q

Acidic functional auxochromes

A

Hydroxyl, carboxyl, and sulphonic groups

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6
Q

What three components are need to make up a dye?

A

An origin (benzene ring), a chromophore and an auxochrome

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7
Q

What is the purpose of xylol in the first step of the hydrating process?

A

To get rid of wax

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8
Q

What is a dye combined with a mordant called?

A

A lake

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9
Q

What two processes must Hematoxylin go through in order to be a dye?

A

Oxidation and mordanting

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10
Q

4 main steps in the H&E stain

A

Nuclear stain, differentiate, blue and counterstain

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11
Q

What is hematoxylin oxidized to?

A

Hematin

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12
Q

How can hematoxylin be oxidized?

A

Either by atmospheric oxidation or by the use of chemical agents

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13
Q

What would nuclei look like if you over oxidized hematoxylin?

A

Reddish-brown/burgundy

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14
Q

2 main classifications of lakes

A

Ferric and aluminum

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15
Q

Which lake classification is unstable?

A

Ferric lakes

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16
Q

Which Hematoxylin dye is unstable and uses a ferric lake?

A

Weigert’s

17
Q

The kind of lake used in Harris hematoxylin

A

Aluminum

18
Q

Purpose of the bluing step in H&E

A

“locks” the hematoxylin in to the cells so it doesn’t leak out and it is more permanent

19
Q

What two elements must be added to a benzene ring for it to become a dye?

A

Auxochrome and chromophore

20
Q

Structure within a dye molecule that confers the property of color

A

Chromophore

21
Q

Function of an auxochrome

A

Enables a dye to attach to the tissue elements of the opposite charge

22
Q

What type of chemical structure is -N=N- termed when found as part of a dye molecule?

A

Chromophore

23
Q

What is the substance that alters the colour of a metachromatic dye called?

A

Chromotrope

24
Q

An intermediate substance required by some stains so that they may combine wtih a tissue structure

A

Mordant

25
Q

What can be used to remove mercury pigment?

A

Alcoholic iodine followed by sodium thiosulfate

26
Q

What is the oxidizing agent in Weigert’s Hematoxylin?

A

Ferric chloride

27
Q

What is the role of ammonium alum in Harris Hematoxylin?

A

Mordant

28
Q

Most synthetic dyes are derivatives of _______

A

benzene

29
Q

Leuco compounds

A

Colourless compounds in which the chromophore group has been destroyed

30
Q

A precipitate removed with alcoholic iodine

A

Mercury pigment

31
Q

Usual refractive index of resinous mounting media

A

1.52

32
Q

In H&E stain, nuclei appear as blue rings with colourless centres. What happened?

A

Hematoxylin staining time too short

33
Q

In H&E, nuclei are staining dull red or brown. What happened?

A

Over-ripe hematoxylin (over-oxidized) or insufficient bluing