Histotechnology Flashcards
(100 cards)
1
Q
also known as numbering
A
accessioning
2
Q
1st step in all histopathologic techniques
A
accessioning
3
Q
identify properly all the specimens without writing the name of the patient to the accompanying tag of the specimens to be processed
A
accessioning
4
Q
Accessioning’s pre-analytical errors
A
- identification
- material reception
- coding
5
Q
small pieces of tissue that appear on a slide that does not belong there
A
floaters
6
Q
1st and most critical step in histotechnology
A
fixation
7
Q
Preserving fresh tissue for examination
A
fixation
8
Q
to preserve the morphologic and chemical integrity of the cell in a life-like manner as possible
A
fixation
primary aim
9
Q
to harden and protect the tissue from the trauma of further handling
A
fixation
secondary aim
10
Q
Give 4 practical considerations of fixation
A
- speed
- penetration
- volume
- duration of fixation
11
Q
Penetration: formalin diffuses into the tissue at approximately
A
1mm/hr
12
Q
Volume: volume of fixative should be ____ the tissue volume
A
20 times
13
Q
True or False
Fibrous organs take longer than small or loosely textured tissues such as biopsies or scrapings
A
True
14
Q
2 mechanisms involved in fixation
A
- additive fixation
- non-additive fixation
15
Q
Fixation Mechanisms
- non-coagulant cross-linking fixatives
- chemical constituent taken into the cell, forming
- *molecular complexes** and stabilizing proteins
A
additive fixation
16
Q
Fixation Mechanisms
- dehydrant coagulant fixatives
- alteration of tissue composition by removing bound water molecule at H bonds within protein molecules
- stabilizes proteins by forming cross-links after water molecule removal
A
Non-additive fixation
17
Q
hydrogen ion concentration (pH)
satisfactory fixation
A
pH 6-8
18
Q
Temperature
- surgical specimen:
- electron microscopy & histochemical specimens:
A
- surgical specimen: RT
- electron microscopy & histochemical specimens: 0-4° C
19
Q
Thickness of Section
- electron microscopy:
- light microscopy:
A
- electron microscopy: 1-2mm2
- light microscopy: 2 cm2
20
Q
buffer presence causes polymerization of aldehyde, with consequent decrease in its effective concentration
A
concentration
21
Q
Primary fixation in buffered formalin: carried out for ____ during the day the specimen is obtained
A
2-6 hours
22
Q
Give 5 fixative categories
A
- aldehyde
- metallic
- picrate
- osmium troxide
- heat fixation
23
Q
Mechanism of preservation: cross-linking agents react with proteins and nucleic acids in the tissue
A
aldehyde fixatives
24
Q
recommended in immunohistochemical studies
A
formaldehyde
25
* produced from oxidation of methyl alcohol
* most common fixative
formaldehyde
26
* best tissue preservative
* penetrates tissue rapidly
* fiffusion rate = **1 cm in 24hrs**
formalin
27
for **CNS tissues** & **general postmortem examinations**
10% formol-saline
28
best fixative for tissues containing **iron pigments**
10% BNF (buffered neutral formalin)
29
Best general tissue fixative
10% BNF
30
fixative of choice for **immunohistochemistry** and **molecular tests**
10% BNF
31
recommended for **routine postmortem tissues**
formol-corrosive/formol-sublimate
32
Allow quick fixation but poor penetration → recommended for **electron microscopy**
glutaraldehyde
33
Preservation of lipids
formol-calcium
34
* excellent trichrome staining
* preservation of cell detail in **tissue photography**
mercuric chloride
35
tissues may produce **black precipitates**
mercuric chloride
36
* most common **mercurial fixative**
* fast preservation
* affinity to nuclear chromatin
Zenker's fluid
37
Zenker-formol is also known as?
Helly's solution
38
preserves cytoplasmic granules
Zenker-Formol (Helly's solution)
39
for **tumor biopsies of the skin**
Heidenhain's Susa
40
used for **bone marrow biopsies**
B-5 fixative
41
Chromate fixative for affinity to nuclear chromatin
chromic acid
42
Chromate fixative which preserves cytoplasmic granules
potassium dichromate
43
Regaud's is also known as?
Moller's
44
demonstration of:
* chromaffin tissues
* Golgi bodies
* mitochondria
* colloid-containing tissues
* mitotic figures
Regaud's
45
* for *Rickettsia* and other bacteria
* for study of **early degenerative process**
Orth's fluid
46
for **acid mucopolysaccharides**
* Wharton's jelly/umbilical cord
lead fixatives
47
* highly explosive when dry
* precipitates are soluble in water
picrate fixatives
48
recommended for **glycogen demonstration** and **aniline stains**
picrate fixatives
49
True or False
Picrate fixatives should be washed in water
before dehydration
False
## Footnote
\*Picrate fixatives *must never* be washed in water before dehydration.
50
Picrate fixatives should always be immersed in ___ to prevent explosion
alcohol
51
* yellow stain is useful for fragmented biopsies
* excellent for **soft and delicate tissues**
Bouin's solution
52
preferred fixative for **connective tissue staining**
Bouin's solution
53
less messy than Bouin's
Brasil's Alcoholic Picroformol
54
* fixes and precipitates:
* nucleoproteins
* chromosomes
* chromatin materials
* for nuclear component studies
Glacial acetic acid
55
Most often used for preservation of cytological smears
alcoholic fixatives
56
**Mechanism of preservation:** dehydration and precipitation of **proteins**
alcoholic fixatives
57
**Alcoholic Fixatives**
blood smears & bone marrow tissues
methanol
58
**Alcoholic Fixatives**
preserves nucleoproteins and nucleic acids for histochemistry and enzyme studies
ethanol
59
**Alcoholic Fixatives**
* most rapid fixative
* recommended for chromosomes study, lymph nodes, urgent studies for glycogen
Carnoy's fluid
60
**Alcoholic Fixatives**
preservation of sputum
Alcoholic formalin (Gendre's fixative)
61
**Alcoholic Fixatives**
mucopolysaccharides
Newcomer's fluid
62
* great fixative for lipids and fats
* excellent fixation for nucleus and cytoplasmic structures
osmium tetroxide fixatives
63
produces black precipitate *(osmic oxide)*
osmium tetroxide
64
Permanently fixes fat
Flemming's solution
65
Removal of acetic acid improves cytoplasmic details
Flemming's solution *without acetic acid*
66
Used for diagnosis of rabies
acetone
67
2 types of heat fixation
1. Direct flaming fixation
2. Microwave fixation
68
Microwave fixation's optimum temperature
45-55° C
69
done before dehydration on fresh specimen or before staining on deparaffinized sections
secondary fixation
70
secondary fixation's mordant
2.5-3% K2Cr2O7
(potassium dichromate)
71
specimen is immersed in a fluid for a longer period of time than the recommended fixation time
overfixation
72
**Reagents Used in Washing Out**
* chromates from tissues fixed with Helly’s, Zenker’s, and Flemming’s solutions
* formalin
* osmic acid
tap water
73
**Reagents Used in Washing Out**
Picric acid from Bouin’s solution
50-70% alcohol
74
**Reagents Used in Washing Out**
mercuric fixatives
alcoholic iodine
75
**removing extracellular** and **intracellular water from tissue** following fixation and prior to **wax infiltration** using increasing concentrations of a dehydrating agent
dehydration
76
Removal of lipoidal material within the tissue
dehydration
77
Give 6 dehydrating agents
1. alcohol
2. acetone
3. dioxane
4. cellosolve
5. THF (tetrahydrofuran)
6. triethyl phosphate
78
most common dehydrating agent
alcohol
79
* for routine dehydration of tissues
* best hydrating agent
ethanol
80
* plant and animal microtechniques
* slow dehydrating agent
butyl alcohol
81
same usage as ethanol and also known as **denatured alcohol**
industrial methylated spirit
82
recommended for many of the processing methods for use in a **microwave oven**
isopropyl alcohol
83
* clear, colorless fluid & most organic solvent
* for dehydrating urgent biopsy specimen
acetone
84
associated with the production of **methamphetamine** (shabu)
acetone
85
dioxane is also known as?
diethylene dioxide
86
Give the 2 agents for the following
* both a clearing and dehydrating agent
* miscible in both water and molten paraffin wax
1. dioxane
2. THF
87
ethylene glycol monoethyl ether is also known as?
cellosolve
88
dissolves cellulose nitrate and acetate
cellosolve
89
* good dehydrating agent
* can remove water easily while producing very little distortion and shrinkage and hardening of tissues
triethyl phosphate
90
For delicate tissues (embryonic and animal tissues), it is recommended to start processing with?
30% ethanol
91
clearing is also known as?
dealcoholization
92
tissues become transparent as a result of the solution raising the refractive index
clearing
93
replacing the dehydrating fluid with a fluid that is **miscible** with both the *dehydrating fluid* and the *impregnating/embedding medium*
clearing
94
dealcoholization purpose of stained sections prior to mounting in?
* Permount
* Clarite or Canada balsam
95
2 agents exempted from the rule of lower boiling point is easier to remove
glycerin & gum syrup
96
* most commonly used & rapid-clearing agent
* for urgent biopsies
xylene/xylol
97
**Clearing Agent**
recommended for CNS tissues and cytological studies
(smooth muscles, skin)
cedarwood oil & clove oil
98
**Clearing Agent**
* volatilizes rapidly in paraffin oven
* easily eliminated from the tissue
benzene
99
**Clearing Agent**
* highly toxic
* dangerous to inhale or prolonged exposure
carbon tetrachloride
100
It is a fluid that is for mitochondria, Golgi elements, and fats
Champy's fluid
