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2G SUMMER > HISTO LEC (FIX) > Flashcards

HISTO LEC (FIX) Flashcards

(122 cards)

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1
Q

Most important step in Histopathology

A

FIXATION

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2
Q

a process
that preserves tissues from decay, thereby preventing autolysis or putrefaction.

A

FIXATION

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3
Q

The primary goal of fixation

A

preserve the morphologic and chemical
integrity of the cell in as life-like a manner as possible

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4
Q

The second goal of fixation

A

to harden and protect the tissue from the
trauma of further handling

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5
Q

results from tissue digestion by intracellular enzymes that are released
when organelle membranes rupture

A

Autolysis

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6
Q

is brought about by microorganisms which may already be present in the specimen

A

Bacterial decomposition or putrefaction

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7
Q

Hypotonic solution on specimen will make the specimen ________________

A

Swell

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8
Q

Hypertonic solution on specimen will make the specimen ________________

A

Shrink

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9
Q

Objectives of Fixation

A

> To Preserve the Tissue
To Prevent Breakdown of Cellular Elements
To Coagulate or Precipitate Protoplasmic Substances

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10
Q

Objectives of Fixation:

stopping all cellular activities so that the
cells can be viewed under the microscope as if they are still in their original
living state

A

To Preserve the Tissue

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11
Q

Objectives of Fixation:

Surgical removal of the tissue from the body will deprive it of oxygen and
nutrition, leading to a degradative chemical process or cell death.

A

To Prevent Breakdown of Cellular Elements

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12
Q

is also known as SUICIDE SAC

A

lysosome

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13
Q

Objectives of Fixation:

Fixation renders insoluble certain tissue components that may otherwise leak
out during subsequent histologic handling

A

To Coagulate or Precipitate Protoplasmic Substances

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14
Q

2 Methods of Fixation

A

Physical and Chemical

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15
Q

methods that include heating, microwaving and cryo-preservation (freeze drying).

A

Physical Method

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16
Q

fixation that is rarely used on tissue specimens, its application being confined to
smears of microorganisms.

A

Heat fixation

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17
Q

usually in the form of freeze drying, has some applications in
histochemistry but is not usually applied to diagnostic tissue specimens

A

Cryopreservation

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18
Q

fixation that is usually achieved by immersing the specimen in the
fixative solution or, in the case of small animals or some whole organs such as a lung, by perfusing or injecting the vascular system with
fixative

A

Chemical fixation

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19
Q

immersing the specimen in the fixative solution

A

immersion fixation

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20
Q

perfusing or injecting the vascular system with
fixative

A

perfusion fixation

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21
Q

chemical constituent of the fixative is
taken in and becomes part of the tissue by forming cross-links or
molecular complexes and giving stability to the protein

A

Additive fixation

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22
Q

fixing agent is not incorporated into the tissue, but alters the tissue composition and stabilizes the tissue
by removing the bound water attached to H-bonds of certain groups
within the protein molecule.

A

Non-additive fixation

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23
Q

Benefits of Fixation

A

> Allows thin sectioning of tissue by hardening tissue
Prevents autolysis and inactivates infectious agents
Improves cell avidity for special stains

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24
Q

Fixation inactivates infectious agents except __________________

A

prion diseases

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25
Specimens should be transferred to fixative quickly or ___________ after surgery as deterioration will commence with the loss of blood supply.
<1 hour
26
Tissues should be fixed in a sufficient volume of solution; generally in a ratio of _______ for penetration to occur in the most efficient manner
20:1
27
Prolonged fixation may be more difficult to reverse and may also result in loss of ________________________
immunohistochemical antigenicity.
28
Main Factors involved in Fixation
> Volume > pH > Temperature > Thickness of the section > Osmolality > Concentration > Duration of the Fixation > Time interval
29
Characteristics of a Good Fixative
> It must be cheap. > It must be stable. > It must be safe to handle. > It must inhibit bacterial decomposition and autolysis. > It must produce minimum shrinkage of tissue.
30
four major groups of fixatives
> aldehydes > oxidizing agents > alcohol based fixatives > > metallic group of fixatives
31
type of Fixatives that act by cross-linking proteins
aldehydes and oxidizing agents
32
type of Fixatives that are protein-denaturing agents
Alcohol based fixatives
33
type of Fixatives that act by forming insoluble metallic precipitates
Metallic fixatives
34
The choice of the fixative is based on ________ and _____________
tissue and anticipated ancillary tests.
35
Type of Fixative based on Composition
SIMPLE FIXATIVES COMPOUND FIXATIVES
36
Fixatives that are made up of only one component substance.
Simple Fixatives
37
Fixatives that are those that are made up of two or more fixatives which have been added together to obtain the optimal combined effect of their individual actions upon the cells and tissue constituents.
Compound Fixatives
38
Example of Simple Fixatives
1. Aldehydes 2. Metallic Fixatives 3. Picric acid 4. Acetic acid 5. Acetone 6. Alcohol 7. Osmium Tetroxide
39
Type of Fixatives according to Action
> MICROANALYTICAL FIXATIVES > CYTOLOGICAL FIXATIVES > HISTOCHEMICAL FIXATIVES
40
Fixatives that are those that permit the general microscopic study of tissue structures without altering the structural pattern and normal intercellular relationship of the tissues in question.
Microanatomical Fixatives
41
Microanatomical Fixatives example
Zenker 's solution Zenker-formal (Kelly 's solution) Bouin's solution Brasil's solution
42
Fixatives that are those that preserve specific parts and particular microscopic elements of the cell itself.
Cytological Fixatives
43
Fixatives that are those that preserve the nuclear structures (e.g., chromosomes) in particular. They usually contain glacial acetic acid as their primary component due to its affinity for nuclear chromatin
Nuclear Fixatives
44
Nuclear Fixatives pH value
4.6 or less
45
Nuclear Fixatives example
Flemming's fluid Carnoy's fluid Bouin's fluid Newcomer's fluid Heidenhain's Susa
46
fixative has been found to react with viruses, and causes the loss of their infective power.
Mercuric chloride
47
Fixatives are those that preserve cytoplasmic structures in particular. They must never contain glacial acetic acid which destroys mitochondria and Golgi bodies of the cytoplasm.
Cytoplasmic Fixatives
48
Cytoplasmic Fixatives pH value
more than 4.6
49
Cytoplasmic Fixatives examples
- Flemming's fluid without acetic acid - Kelly's fluid - Formalin with "post-chroming" - Regaud 's fluid (Muller 's fluid) - Orth 's fluid
50
Fixatives that are those that preserve the chemical constituents of cells and tissues.
Histochemical Fixatives
51
Histochemical Fixatives examples
- Formal Saline 10% - Absolute Ethyl Alcohol - Acetone - Newcomer's Fluid
52
is the process of placing an already fixed tissue in a second fixative
Secondary Fixation
53
Connective tissue stain
Masson's trichrome
54
Collagen stainn
Mallory's aniline blue stain
55
for striated muscle stain
phosphotungstic acid-hematoxylin (PTAH) stain
56
Mordant for special stain
Zenker's Solution
57
is the process of removing excess fixative from the tissue after fixation in order to improve staining and remove artefacts from the tissues.
Washing out
58
50-70% alcohol is used to wash out excess amount of ________________
picric acid (Bouin's solution)
59
is used to remove excessive mercuric fixatives.
Alcoholic iodine
60
Artifact found in surgical specimens particularly in liver biopsies, associated with an intense eosinophilic staining at the center of the tissue in H&E stained sections
Crush Artifact
61
The most widely used fixative for routine histology is _________________
10% neutral buffered formalin
62
recommended for fixation of central nervous tissues and general post-mortem tissues for histochemical examination
10% Formal-Saline
63
also recommended for the preservation of lipids, especially phospholipids
10% Formal-Saline
64
Used best for Fe pigments
10% Neutral-Buffered Formalin
65
solutions that were devised as alternatives to mercuric chloride formulations
Zinc formalin
66
recommended for routine post-mortem tissues
Formol-Corrosive
67
alcoholic fixative, sputum/ cytology
Gendre's
68
Fixative for lipid preservation
Formol-calcium
69
Fixative for Electro cytochemistry
> Acrolein > Karnovsky’s paraformaldehyde- glutaraldehyde
70
> Larger molecule than formaldehyde, diffuses more slowly > Rapid and reversible changes, fixes quickly, is well suited for electron microscopy > Gives the best overall cytoplasmic and nuclear detail
Glutaraldehyde
71
Gas produced by the oxidation of methyl alcohol, and is soluble in water to the extent of 37-40%weight in volume.
Formaldehyde
72
> Polymerized form of formaldehyde. > Suitable for paraffin embedding and sectioning, and also for immunocytochemical analysis
Paraformaldehyde
73
Formalin artifacts characterized by Brown or Black Granules
Acid Formaldehyde Hematin
74
Acid Formaldehyde Hematin is removed by: ___________________
> Kardaswitch > Lilies > Alcoholic Picric Acid
75
Formalin artifacts characterized by White Precipitate
Paraformaldehyde
76
Paraformaldehyde is removed by; ____________
> Filtration > Methanol > Heat
77
Kardaswitch components
70% ethanol, 28% ammonia water
78
Lilies components
hydrogen peroxide, acetone, ammonia water
79
MAIN TYPES OF METALLIC FIXATIVES
> Mercurial > Chromate Fixative > Lead Fixative
80
most common metallic fixative
Mercurial Fixative
81
Adv: * Demonstration of loose cells * Good for metachromatic staining * Preservation of details in photography Dsv: *Troublesome fixative *Corrode all metals except monel (nickel alloy) *Lysis of RBC
Mercurial Fixative
82
Mercurial Fixatives that is Compatible with most stains
Zenkers Fluid (HAC Primary Additive)
83
Mercurial Fixatives that is Used as microanatomical Fixative
Zenkers - Formol/ Hellys (Kellys) Solution (Formalin Primary Additive)
84
Mercurial Fixatives that is Gold standard fixative in parasitology
Schaudins Fluid
85
Mercurial Fixatives that is for Tumor Biopsy of the Skin
Heidenhains SuSa
86
SuSa meaning
Su- Sublimate mercuric chloride Sa- Saure trichloroacetic acid
87
corrosive sublimate "corrodes mucous, sublime at w/ low heat
Sublimate mercuric chloride
88
Precipitates protein
Saure trichloroacetic acid
89
Mercurial Fixatives that is for Bone marrow biopsies
B-5
90
Mercurial Fixatives that is a Nuclear Fixative
Carnoy-Lebrun Fluid Ohlmacher's Fluid
91
Adv: * For demonstration of chromaffin tissue (adrenal medulla, mitochondria, Golgi apparatus) *Good for RBC demonstration Dsv: * Fixative darkens during prolonged standing * Easy deterioration
CHROMATE FIXATIVE (OXIDIZING)
92
Chromate fixative that enables the Formation of artifacts (fine yellow brown)
1-2% Chromic Acid
93
1-2% Chromic Acid artifact can be removed by ___________
Acid OH
94
Chromate fixative that preserves lipid and mitochondria @ pH 4.5 – 5.2
Potassium Dichromate
95
Chromate fixative that preserves Mitochondria
Regauds/ Moller's Fluid (3% K2Cr2O7)
96
Chromate fixative that demonstrates rickettsiae and early degenerative process
Orth's Fluid ( 2.5% K2Cr2O7)
97
Adv: *recommended for acid mucopolysac *fixes connective tissue mucin Dsv: *takes up CO2 forming Lead Carbonate in prolonged standing.
Lead Fixative
98
Lead Carbonate can be removed by _________ or adding __________ to dissolve residue.
filtration, acetic acid
99
Adv: * Excellent fixative for glycogen Dsv: *Causes RBC lysis *Dry form causes explosion
PICRIC ACID
100
Main types of Acid Fixative
1. Picric Acid 2. Osmic Acid 3. Glacial Acetic Acid 4. Trichloroacetic Acid
101
Adv: * Fixes conjugated fats &lipids * Precipitates & gels proteins Dsv: *very expensive *- Poor penetration, irritatingvapor*- inhibits hematoxylin
OSMIC ACID
102
Adv: * Fixes/precipitates proteins *Useful for study of nuclear materials (chromosomes) Dsv: *Swells tissue (counteract effect of Hg fix’v) *Contraindicated for cytoplasmic fixation
GLACIAL ACETIC ACID
103
Adv: * Incorporated into compound fixative * Suitable only for small pieces of tissues/bones
TRICHLOROACETIC ACID
104
Picric acid is a
* Fixative * Stain * Decalcifying Agent
105
Better and less messy than Bouin’s
Brasil's alcoholic Picroformol
106
Bouins Fluid components
Picric Acid, Formalin, & Glacial Acetic Acid
107
Brasil's alcoholic Picroformol components
Picric Acid, Formalin, Ethanol, Trichloroacetic Acid)
108
* Produces Osmic oxide ( black precipitate) * Prevention - +saturated mercuric chloride * Remedy – dissolved in cold water
OSMIC ACID
109
Used for Electron microscopic studies and Kept in dark to prevent light reduction
OSMIC ACID
110
Acid Fixative excellent for nuclear structures
Flemming's Solution
111
Acid Fixative that is chromic + osmic and is for cytoplasmic, mitochondria
Flemming's Solution without acetic acid
112
ADVANTAGES: *Good for small tissue fragments *Initiates dehydration DISADVANTAGES: (to the tissue as a whole) *Severe shrinkage, RBC lysis *Overhardening of tissue *Polarization
ALCOHOL FIXATIVE
113
ALCOHOL FIXATIVE Used in blood and bone marrow smears
Methanol
114
ALCOHOL FIXATIVE that is Most rapid, used for Chromosomes and lymph glands
Carnoy’s
115
ALCOHOL FIXATIVE that is for Preserving sputum
Gendre’s (Alcoholic Formalin)
116
ALCOHOL FIXATIVE that is for Cytological smears
Ethanol
117
ALCOHOL FIXATIVE that is Fixative for touch prep
Isopropyl Alcohol
118
ALCOHOL FIXATIVE that is for Mucopolysaccharides . at the same time is a Nuclear and histochemical fixative
Newcomer’s
119
Oven Temperature
56-60 deg C for 2 hours
120
Blower Temperature
45 -55 deg C for 30-45 mins
121
Physical fixation technique used for emergency
Direct heating
122
incubator temperature
37 deg C overnight for nervous tissue

2G SUMMER (5 decks)

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