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Histopath Midterm > Introduction Up To Fixation > Flashcards

Introduction Up To Fixation Flashcards

1
Q

True or False. Medical Technologists do gross examination.

A

Gross exam is done by the pathologist in the laboratory.

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2
Q

In gross exam, the pathologist will get what type of information?

A

dimension of the specimen/color/gross weight/consistency

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3
Q

What is the required size of the specimen?

A

3cm x 2cm

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4
Q

What is the required thickness of the specimen?

A

3-5mm

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5
Q

Step in tissue processing that involves preservation

A

fixation

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6
Q

What is the primary goal of fixation?

A

To preserve tissues as close to the original as possible

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7
Q

What are the secondary goals of fixation?

A

Harden the tissue to facilitate easy cutting (into thin slices)
Protect the tissue from trauma of further handling that might be caused by different reagents used in tissue processing

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8
Q

If processing lung specimen, the required size is _______.

A

1-2cm is the required size

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9
Q

What is the required pH in fixation?

A

Should be between 6-8

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10
Q

What is the required Osmolality when fixing a specimen? (According to book and during practice)

A

Book: Slightly hypertonic
In practice: isotonic

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11
Q

Hypotonic causes _______.

A

swelling

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12
Q

Hypertonic causes __________.

A

shrinking

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13
Q

True or False. In fixation, we do not use concentrated solutions because it could be very damaging to the tissue.

A

True

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14
Q

True or False. In fixation, we use 100% formalin.

A

we use 10% formalin rather than 100% formalin

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15
Q

Maximum effectiveness of fixative should be ________ the volume of the specimen.

A

20x

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16
Q

Ratio of fixative to tissue is _____.

A

15-20:1

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17
Q

When does preservation happen?

A

Preservation happens when the fixative penetrate the tissue

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18
Q

What is the penetration rate of formalin?

A

1mm per hour

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19
Q

True or False. Osmium tetroxide is used for histochemistry.

A

False, it is one of the few fixatives used for Electron Microscopy

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20
Q

What is the ratio of fixative and volume of specimen when using Osmium Tetroxide as fixative.

A

5-10: 1

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21
Q

How long does fixation take to be carried out?

A

24-48 hours

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22
Q

Temperature in Manual Fixation.

A

Room temp

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23
Q

Temperature of fixation for Electron Microscopy and Histochemistry.

A

0-4degC

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24
Q

Temperature when doing fixation using Autotechnicon.

A

40degC (process is shorter compared to manual fixation since it is an automatic processor that uses heat)

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25
Q

40degC (process is shorter compared to manual fixation since it is an automatic processor that uses heat

A

True

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26
Q

What are the factors being considered when choosing the right fixative?

A

Urgency of the case, Type of tissue to be processed, Tissue structure to be studied, Staining technique to be applied, Type of section to be made

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27
Q

If an urgent biopsy is required, we need to use __________.

A

fast-acting fixative

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28
Q

What is the most commonly used fixative because it is fast- acting.

A

Formalin

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29
Q

Used to preserve brain tissues for the diagnosis of rabies.

A

Carnoy’s solution and acetone

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30
Q

True or False. Bouin′s solution can be used for kidney specimens.

A

False, Bouin′s solution cannot be used for kidney specimens.

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31
Q

True or False. Brasil`s fluid is good in preserving glycogen.

A

True

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32
Q

When preserving fats, why is acetone not used as a fixative?

A

Because acetone dissolves fats

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33
Q

True or False. Acetone can be used when preserving enzymes (lipases and phosphatases)

A

True

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34
Q

What is the routine stain in HistoPath?

A

H&E (Hematoxylin and Eosin)

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35
Q

Why is the H&E staining the routine stain in histopath?

A

because it is compatible with many fixatives

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36
Q

True or false. Osmium tetroxide is an example of a fixative that can inhibit hematoxylin.

A

True

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37
Q

Osmium tetroxide can inhibit _______.

A

Hematoxylin

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38
Q

True or false. You can use osmium tetroxide as a fixative when the specimen will be stained with hematoxylin.

A

False, because it inhibits hematoxylin.

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39
Q

What are the two types of sections that can be made?

A

Either serial or individual

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40
Q

What are the factors that will retard fixation?

A

Cold temperature, Presence of blood and presence of mucus, Size and thickness of the specimen, Presence of fats

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41
Q

Why do we not place specimens in the refrigerator when fixing?

A

because the process will take longer

42
Q

True or False. If the specimen is covered with blood and/or mucus, the fixative can penetrate the tissue easily because the fixative will be diluted with the blood/ mucus.

A

False, the fixative cannot penetrate the tissue easily, so the process will take longer

43
Q

Remedy when the specimen is covered with blood or mucus.

A

remove blood and mucus using NSS

44
Q

True or False. If the tissue is bigger and thicker, the longer the fixation time.

A

True

45
Q

True or False. If the specimen is covered with fats, the fixative cannot penetrate the tissue easily, so the process will take longer.

A

True

46
Q

Remedy when the specimen is covered with fats.

A

cut the specimen thinly to ensure rapid entry of fixative to tissues

47
Q

What are the factors that accelerate fixation time?

A

Size and thickness of the specimen, Application of heat, agitation

48
Q

True or False. If specimen is smaller, fixation time will be longer.

A

False, fixation time will be shorter

49
Q

True or False. Application of heat will retard fixation time.

A

It will accelerate fixation time.

50
Q

What will application of heat do to the specimen? ______,________.

A

Shorten fixation time and destroy tissue

51
Q

During fixation, application of heat with what range of temperature can acclerate fixation time?

A

37-56 degCelsius only because beyond that, the tissue could be destroyed (37-56 degrees Celsius)

52
Q

The use of autotechnicon has continuous agitation which causes ________.

A

rapid entry of fixative to tissue

53
Q

What are the problems encountered during fixation?

A

Lost of substances soluble in fixing agents, incomplete fixation or inadequate fixation, Overfixation, Inadequate washing

54
Q

Possible reason for loss of substance after fixation.

A

Wrong choice of fixative

55
Q

Indication of incomplete fixation or inadequate fixation.

A

If the specimen is soft after fixation

56
Q

Indication of Overfixation.

A

If the specimen is too hard after fixation

57
Q

Indication of Inadequate washing.

A

If the specimen after fixation contains artifacts

58
Q

What are the 2 types of fixative aaccording to mechanism of actions.

A

Non-additive fixatives, Additive fixatives

59
Q

What do you call the fixatives that do not bind or do not become part of the tissue.

A

Non-additive fixatives

60
Q

What do you call the fixatives that bind or become part of the tissue?

A

Additive fixatives

61
Q

All fixatives are additives EXCEPT for _______ and _________.

A

acetone and alcohol

62
Q

What are the types of fixatives as to actions?

A

Microanatomical Fixatives, Cytological Fixatives, Histochemical fixatives

63
Q

Type of fixative used to preserve parts of the cell such as nucleus and cytoplasm.

A

Cytological Fixatives

64
Q

Cytological fixatives are subdivided into _____ and _____.

A

Nuclear fixatives and Cytoplasmic fixative

65
Q

Used to preserve nuclear chromatin or parts of the nucleus.

A

Nuclear fixatives

66
Q

What are the examples of nuclear fixatives?

A

Carnoy’s, Bouin’s, Newcomer’s, Heidenhain’s Susa, Flemmings with HAc

67
Q

What are the examples of cytoplasmic fixatives?

A

Regaud’s/Moller’s, Orth’s, Formalin with post chroming, Flemming’s without HAc

68
Q

Used to preserve cytoplasmic organelles such as mitochondria, golgi apparatus etc.

A

Cytoplasmic Fixatives

69
Q

Fixatives that are used to preserve the chemical components of tissues.

A

Histochemical fixatives

70
Q

_______ is used when preserving enzymes.

A

Acetone

71
Q

How to prepare 1L of 10% formalin?

A

Combine 100mL of 37-40% formalin to 900mL of distilled water

72
Q

If formalin is stored for a long time, it has a tendency to ________.

A

precipitate

73
Q

What will you add to formalin to prevent precipitation of formaldehyde to white paraformaldehyde for prolonged storage.

A

10% methanol

74
Q

Enumerate METALLIC FIXATIVES.

A

Mercuric Chloride Fixatives, Chromate Fixatives, Lead Fixative

75
Q

Fixatives that contains mercuric chloride as the basic ingredient.

A

Mercuric Chloride Fixatives

76
Q

What is the most common metallic fixative that is excellent for trichrome staining and tissue photography?

A

Mercuric Chloride Fixatives

77
Q

Disadvantage of Mercuric Chloride Fixatives.

A

They left black mercuric precipitate

78
Q

Proposed as mercuric chloride substitute but is also toxic to man.

A

Zinc sulfate

79
Q

Fixative that preserves liver, spleen, connective tissue, and nuclei.

A

Zenker’s fluid

80
Q

Fixative that preserves bone marrow.

A

B5

81
Q

Fixative for tumor skin biopsies preservation.

A

Heidenhain’s Susa

82
Q

Fixative that preserves pituitary gland, bone marrow, spleen and liver.

A

Helly’s fluid (Zenker formol or formol zenker)

83
Q

All chromate fixatives contain ________.

A

potassium dichromate

84
Q

Type of chromate fixative that preserves carbohydrates.

A

1-2% chromic acid

85
Q

Type of chromate fixative that preserves lipids and mitochondria.

A

3% potassium dichromate

86
Q

What does Regaud’s or Moller’s preserve?

A

mitochondira, RBC and colloid containing tissues

87
Q

What will be used to prevent Rickettsiae and other bacteria, tissue necrosis?

A

Orth’s fluid

88
Q

When will you use Lead Fixative?

A

When preserve acid mucopolysaccharide

89
Q

What are the 2 general methods of fixation?

A

Chemical Fixation, Physical fixation

90
Q

Fixation that uses chemical fixatives.

A

Chemical Fixation

91
Q

This method of fixation involves immersing the specimen in the fixative and is often done in histopath.

A

Chemical Fixation

92
Q

Routine tissue fixative.

A

10% formalin

93
Q

Fixation that uses heat fixation, microwave technique, etc.

A

Physical Fixation

94
Q

Fixation method that involves thermal coagulation of proteins.

A

Heat fixation

95
Q

Method of fixation that is used in micro, bacte to prepare bacterial smears.

A

Heat fixation

96
Q

Method of fixation that can be done in preparing frozen sections.

A

Physical Fixation

97
Q

For museum preparations, the ration of fixative to volume of specimen is ______.

A

50-100: 1

98
Q

Used to wash out excess amounts of mercuric fixatives.

A

Alcoholic Iodine

99
Q

Used to wash out excess amount of picric acid fixatives.

A

50-70% alcohol

100
Q

Often used in conjunction with other fixatives to produce a compound fixative, aside from glacial acetic acid. It is also considered as a weak and slow decalcifying agent

A

TCA (trichloro acetic acid)

101
Q

Fixative for enzyme histochemistry.

A

4% formaldehyde and formal saline

Histopath Midterm (8 decks)

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