SEMIS Flashcards
(154 cards)
1
Q
What is the first step in risk management within a hospital facility?
A
Identify all hazards in and emanating from the laboratory
2
Q
List the top 6 workplace hazards.
A
- Biological
- Physical
- Chemical
- Psychological
- Ergonomic
- Safety
3
Q
What must standard operating procedures (SOP) include?
A
Control of hazardous substances, risk assessments, and other health and safety information
4
Q
What is a planar concave microtome knife used for?
A
Cutting very soft samples like fascia, tendons, adipose tissues, and connective tissues
5
Q
What types of materials are wedge profile knives used for?
A
Moderately hard materials such as epoxy or cryogenic samples
6
Q
What is the function of a cryostat?
A
To preserve frozen tissue samples and slice them thin enough for microscopic examinations
7
Q
What is the difference between formaldehyde and formalin?
A
Formaldehyde is a gas that is dissolved in water to form formalin, which is a saturated solution of formaldehyde
8
Q
Fill in the blank: The __________ is an instrument for cutting extremely thin sections for examination under a microscope.
A
Microtome
9
Q
What are the major equipment types used in histotechnology?
A
- Microscope
- Microtome
- Cryostat
- Autotechnicon
- Automated coverslipper
- Automated H and E stainer
10
Q
True or False: Poor equipment handling can affect the diagnosis and prognosis of a patient.
A
True
11
Q
What should be maintained for every piece of laboratory equipment?
A
A current file containing name, manufacturer, model number, serial number, and maintenance records
12
Q
What is the hazard associated with acetic acid?
A
Irritation to skin, eyes, and respiratory system upon direct contact
13
Q
What is the recommended storage condition for isopentane?
A
In a refrigerator or freezer suited for explosive atmospheres
14
Q
List three types of staining protocols mentioned.
A
- 70% Ethanol for tissue fixation
- Haematoxylin for nuclease staining
- Eosin stain for cytoplasm staining
15
Q
What is the risk associated with chloroform?
A
Toxic when inhaled or ingested, and can cause disorientation, loss of consciousness, and death
16
Q
What should be done with concentrated acids?
A
They should be added to water, not water to acid, to prevent splashing
17
Q
What is the purpose of a smear preparation in cytological exams?
A
To spread cellular materials over a slide for examination
18
Q
What are the effects of prolonged exposure to toluene?
A
Impaired memory, poor coordination, mood swings, and permanent nerve damage
19
Q
What is the characteristic of picric acid when dry?
A
It is explosive when dry or combined with metals
20
Q
Fill in the blank: The method used to immerse a tissue specimen in isotonic saline solution for examination is called __________.
A
Teasing or dissociation
21
Q
What is the significance of keeping tissue samples intact in histotech?
A
To provide fast and accurate results
22
Q
What precautions should be taken when handling formaldehyde?
A
Workers should be periodically monitored for exposure levels
23
Q
What is the purpose of smear preparation?
A
Useful in cytological exams, particularly Pap smears for cancer diagnosis
Smear preparation involves spreading cellular materials lightly over a slide.
24
Q
Describe the process of smear preparation.
A
Place a drop of secretion on one slide, move two slides in opposite directions to initiate material flow
This is done in one single uninterrupted motion.
25
What are recommended specimens for smear preparation?
* Serous
* Concentrated sputum
* Enzymatic lavage from GIT
* Blood smears
26
What is a touch preparation?
Tissue is pressed onto a slide to transfer cells directly for examination
## Footnote
Cells can be examined without destroying their intercellular relationships.
27
What is a frozen section?
Fresh tissue frozen immediately for rapid diagnosis
## Footnote
Results are usually obtained within 5-15 minutes.
28
What types of specimens can be processed as frozen sections?
* Sputum
* Pleural
* Peritoneal
* CSF
29
What is the purpose of streaking in laboratory procedures?
To obtain a uniform distribution of secretion on a slide
## Footnote
Too thick or too thin samples are unsuitable for examination.
30
Define cryostat.
A cold chamber with a built-in microtome that maintains a temperature of -10 to -20˚C.
31
What are the applications of frozen sections?
* Rapid pathologic diagnosis during surgery
* Diagnostic and research enzyme histochemistry
* Demonstration of soluble substances (lipids and carbohydrates)
32
What is the most rapid method of freezing tissues?
Liquid nitrogen
## Footnote
It is used in histochemistry and during operative procedures.
33
What are some disadvantages of using liquid nitrogen for freezing?
* Soft tissue may crack
* Overcooling can damage biopsy blocks
* Uneven cooling can complicate diagnostic interpretation
34
What is the significance of the fixative in histotechnology?
Preserves the morphologic and chemical integrity of cells and prevents decomposition and distortion.
35
What are the basic mechanisms in fixation?
* Additive fixation
* Non-additive fixation
36
What does additive fixation involve?
The chemical constituent of the fixative becomes part of the tissue, forming cross-links
## Footnote
Examples include formalin and osmium tetroxide.
37
What does non-additive fixation involve?
The fixing agent alters the tissue composition without becoming part of the tissue
## Footnote
Examples include alcoholic fixatives like ethanol and methanol.
38
List the main factors in fixation.
* Hydrogen ion concentration
* Temperature
* Thickness of section
* Osmolality
* Concentration
* Duration of fixation
39
What are the effects of fixatives on tissues?
* Harden tissues
* Make cells resistant to damage
* Inhibit bacterial decomposition
* Increase optical differentiation
* Act as mordants for staining
40
What are the characteristics of a good fixative?
* Cheap
* Stable
* Safe to handle
* Kill cells quickly
* Minimal shrinkage
* Permit rapid penetration
41
What are the two categories of fixation according to action?
* Microanatomical fixatives
* Cytological fixatives
42
What is the purpose of nuclear fixatives?
Preserve nuclear structures such as chromosomes
## Footnote
Usually contain glacial acetic acid.
43
What is the importance of lipid fixation?
Lipids are largely removed during tissue preparation; cryostat sections are used for demonstration
## Footnote
Fixatives containing mercuric chloride can effectively preserve lipids.
44
What fixatives are recommended for glycogen fixation?
* Alcohol-based fixatives
* Rossman's fluid
* Cold absolute alcohol
45
What are the pros and cons of acrolein as a fixative?
Pros: Preserves microanatomy with minimal distortion; Cons: Slow fixative, requires 24 hours or longer.
46
What is the routine turn-over time for surgical pathology results?
24 hours
47
What is the routine turn-over time for frozen section results?
5-15 minutes
48
What is the recommended storage time for pathology/bone marrow slides?
10 years
49
What must be included in the documentation for pathology reports?
* Surgical Pathology
* Cytology
* Autopsy Report
50
True or False: Fixation is the first and most critical step in histotechnology.
True
51
Fill in the blank: The primary fixation in buffered formalin is usually carried out for _______ hours.
2-6
52
What is Acrolein commonly mixed with for tissue fixation?
Glutaraldehyde or formaldehyde
53
What are the advantages of using Acrolein as a fixative?
* Penetrates and fixes tissues evenly
* Preserves microanatomic and cytologic details with minimal shrinkage and distortion
* Preserves enzymes and nucleoproteins
* Demonstrates fats and mucin
* Ideal for most staining techniques
54
What is a major disadvantage of using Acrolein?
Slow fixative, requires 24 hours or longer
55
What is the most widely used fixative in histology?
10% formalin
56
What is the common dilution ratio for preparing 10% formalin?
1:10 or 1:20
57
What is a disadvantage of using unbuffered formaldehyde?
* Reduces basophilic and eosinophilic staining
* Forms brown pigment granules on blood-containing tissues
58
What is 10% neutral buffered formalin primarily used for?
Preservation and storage of surgical, post-mortem, and research specimens
59
What are the components of 10% neutral buffered formalin?
* Anhydrous sodium dihydrogen phosphate
* Anhydrous disodium hydrogen phosphate
* 40% formaldehyde
* Distilled water
60
What is the fixation time for 10% neutral buffered formalin?
4-24 hours
61
What is the purpose of adding sodium chloride to 10% formal saline?
To create a simple microanatomical fixative
62
What are the components of 10% formol saline?
* Saturated formaldehyde (40% by weight volume)
* Sodium chloride
* Distilled water
63
What is the recommended fixation time for 10% formol saline?
24 hours at 35 °C, 48 hours at 20-25 °C
64
What is a major advantage of formaldehyde as a fixative?
* Cheap
* Readily available
* Preserves fat and mucin
65
What is a disadvantage of formaldehyde in tissue fixation?
Can cause allergic dermatitis
66
What is the main advantage of glutaraldehyde over formalin?
More stable effect on tissues, firmer textures
67
What is the primary use of mercuric chloride in fixation?
Commonly used as a secondary fixative
68
What solution is Zenker’s fluid composed of?
* Mercuric chloride stock solution
* Glacial acetic acid
69
What are the pros of using Zenker's fluid?
* Fairly rapid and even fixation
* Compatible with most stains
70
What is a major con of Zenker's fluid?
Poor penetration
71
What does the term 'inert' mean in the context of fixatives?
Chemically inactive or no chemical reaction
72
What is the purpose of Dezenkerizing?
To remove mercuric pigment deposits from tissues
73
List the reagents needed to dezenkerize tissues.
* Lugol's iodine
* Sodium thiosulfate
74
What is the fixation time for Heidenhain's Susa?
3-12 hours
75
What are the components of B-5 fixative?
* Distilled water
* Mercuric chloride
* Anhydrous sodium acetate
76
What is a significant disadvantage of using picric acid as a fixative?
Causes RBC hemolysis
77
What is a key feature of Bouin's solution?
Recommended for fixation of embryos and pituitary biopsies
78
What is the primary disadvantage of using ethyl alcohol for fixation?
Destroys cytoplasmic structures
79
What does the term 'microanatomic fixative' refer to in histology?
A fixative that preserves tissue structure for microscopic examination
80
What is the main characteristic of compound fixatives?
Always correlated with other fixatives like Carnoy’s, Bouin’s, and Heidenhain’s Susa.
81
At what temperature does the compound fixative solidify?
17 °C
82
What are the advantages of using formalin as a fixative?
* Fixes and precipitates nucleoproteins
* Precipitates chromosomes and chromatin materials
* Essential constituent of most compound nuclear fixatives
* Causes tissues containing collagen to swell
83
What are the disadvantages of using formalin for cytoplasmic fixation?
Destroys mitochondria and Golgi elements of the cells.
84
What is the function of alcoholic fixatives?
Denatures and precipitates proteins by destroying hydrogen and other bonds.
85
What concentration range is required for alcoholic fixatives?
70-100%
86
What are the pros of using alcoholic fixatives?
* Ideal for small tissue fragments
* Can be used as both a fixative and dehydrating agent
* Excellent for glycogen preservation
* Preserves nuclear stains
87
What are the cons of using low concentrations of alcoholic fixatives?
* May cause RBC hemolysis
* Inadequately preserves leukocytes
* Dissolves fats and lipids
* Causes polarization of glycogen granules
88
What is the fixation time for methyl alcohol 100%?
Prolonged fixation for more than 48 hours may overharden tissue.
89
What is Carnoy's fluid primarily used for?
Fixing chromosomes, lymph glands, and urgent biopsies.
90
What are the components of Carnoy's fluid?
* Absolute alcohol
* Chloroform
* Glacial Acetic Acid
91
What is the fixation time for Carnoy's fluid?
1-3 hours
92
What is the main advantage of using osmium tetroxide?
Fixes conjugated fats and lipids permanently.
93
What are the disadvantages of osmium tetroxide?
* Very expensive
* Poor penetrating agent
* Readily reduced by contact with organic matter
* Prolonged exposure may cause blindness
94
What is the purpose of secondary fixation?
To facilitate and improve the demonstration of particular substances.
95
What factors slow down the fixation of tissues?
* Size and thickness of tissue specimen
* Presence of mucus
* Presence of fat
* Presence of blood
* Cold temperature
96
What factors enhance the fixation of tissues?
* Size and thickness of tissues
* Agitation
* Moderate heat (37-56 °C)
97
What is the process of dehydration in tissue preparation?
Removing intracellular and extracellular water from the tissue after fixation.
98
What are commonly used dehydrating agents?
* Alcohol
* Ethanol/Ethyl Alcohol
* Isopropanol/Isopropyl Alcohol
* Methanol/Methyl Alcohol
* Butanol/Butyl Alcohol
* Dioxane/Diethylene Dioxide
99
What is the ideal volume of dehydrating agent needed?
Not less than 10x the volume of tissue to be dehydrated.
100
What is the purpose of clearing in tissue preparation?
To replace the dehydrating agent with a fluid that will dissolve the wax.
101
What is a common clearing agent?
Xylene
102
What is the characteristic of xylene as a clearing agent?
It is the most rapid clearing agent.
103
What is the definition of decalcification?
Technique for removing minerals from bone or other calcified tissue.
104
What can overcalcification lead to?
Hard overstaining of tissues.
105
What is the purpose of decalcification in tissue processing?
To remove calcium from tissues for examination, particularly in bones and associated pathologies
## Footnote
Decalcification is essential for diagnosing tumors, infections, and analyzing degenerative processes.
106
What are some common tissues that may undergo decalcification?
Tissues undergoing degenerative processes, including:
* Bone
* Bone marrow
* Blood vessel walls
* Kidney
* Lung
* Areas with metastatic calcification
## Footnote
These tissues may exhibit calcium deposits that require removal for proper analysis.
107
What is a good decalcifying agent characterized by?
Must be capable of:
* Completely removing calcium salts
* Not significantly damaging cells and tissue components
* Preserving staining capacity of the nucleus
## Footnote
Effective decalcifying agents maintain tissue integrity while allowing for microscopic analysis.
108
List four types of agents used for calcium removal during decalcification.
* Acids
* Chelating agents
* Ion exchange resins
* Electrical ionization (electrophoresis)
## Footnote
Each type has different applications and effects on tissue morphology.
109
What factors influence the rate of decalcification?
* Concentration of active agent
* Temperature
* Agitation
* Fluid access
## Footnote
Each factor can impact the efficiency and effectiveness of the decalcification process.
110
True or False: Higher concentrations of decalcifying agents always result in less tissue damage.
False
## Footnote
Higher concentrations can increase tissue shrinkage and morphological damage.
111
Name three commonly used acid decalcifying agents.
* Nitric acid
* Hydrochloric acid
* Formic acid
## Footnote
These agents vary in effectiveness and impact on tissue morphology.
112
What is the main disadvantage of using nitric acid as a decalcifying agent?
Inhibits nuclear stains and can destroy tissues, especially in concentrated solutions
## Footnote
This limits its application for certain diagnostic purposes.
113
Fill in the blank: The most rapid decalcifying agent recommended for urgent works is _______.
Phloroglucin nitric acid
## Footnote
It allows for quicker processing times but may lead to poor nuclear staining.
114
What is the role of EDTA in decalcification?
It acts as a chelating agent that combines with calcium ions to facilitate their removal
## Footnote
While effective, it is slow-acting and requires a large volume.
115
What is the purpose of the impregnation process in histology?
To fill natural cavities and spaces in tissues with a medium that allows cutting of thin sections
## Footnote
This process is crucial for maintaining tissue structure during sectioning.
116
What is a common method for impregnation in histology?
* Paraffin wax impregnation
* Celloidin wax/Collodion impregnation
* Gelatin impregnation
## Footnote
Each method has specific applications based on the nature of the tissue being processed.
117
What is the significance of maintaining the temperature of paraffin during embedding?
It must be maintained 2-5°C above the melting point to prevent tissue shrinkage and hardening
## Footnote
Proper temperature control is essential for optimal embedding.
118
What is the recommended reagent to tissue ratio for fixation?
20:1
## Footnote
This ensures adequate fixation of the tissue specimen.
119
What is the process of embedding in histology?
The process of placing impregnated tissue into a mold containing an embedding medium to solidify
## Footnote
Proper embedding is crucial for maintaining tissue orientation and integrity during sectioning.
120
What is a potential consequence of improper labeling in a laboratory setting?
Mislabeling can lead to inaccurate results and jeopardize patient diagnosis
## Footnote
Accurate labeling is essential for maintaining the integrity of laboratory processes.
121
What is the purpose of using cold water in tissue processing?
To solidify tissues, giving them a firmer consistency and better support for section cutting.
## Footnote
This facilitates the cutting of sections.
122
What is a cold plate used for in tissue processing?
To easily solidify the embedding mold.
## Footnote
It aids in the hardening process of the tissue embedding.
123
What is the purpose of a forceps warmer?
To properly arrange or have a proper orientation of tissue samples during manipulation.
124
What is a paper boat used for in tissue embedding?
For embedding celloidin and paraffin blocks.
125
What is the celloidin/nitrocellulose method recommended for?
Embedding hard tissues such as bones and teeth and large sections of whole organs like eyes.
126
What is Low Viscosity Nitrocellulose (LV.N)?
A form of celloidin soluble in equal concentrations of ether and alcohol.
127
What are the types of blocking-out molds mentioned?
1. Leukhart's embedding mold
2. Compound embedding mold
128
What does the double embedding method involve?
Tissues are infiltrated with celloidin and subsequently embedded in paraffin mass.
129
What is the plastic or resin method especially good for?
Light microscopic studies, particularly in hard tissues and high-resolution light microscopy.
130
What are some types of plastics used in embedding?
Epoxy plastics, Polyester plastics, Acrylic plastics.
131
What is the purpose of microtomy?
To trim and cut processed tissues into uniformly thin slices for microscopic studies.
132
What is trimming in the context of microtomy?
Cutting off excess wax from the block to expose the tissue surface.
133
What is sectioning or section cutting?
Cutting tissues into uniformly thin slices with the aid of a machine.
134
What is a microtome?
A machine/instrument designed for accurately cutting thin slices of tissues.
135
What is the most common solution used during frozen sectioning?
Liquid nitrogen.
136
What does honing involve?
The removal of gross nicks and irregularities on the knife edge.
137
What is the direction used during honing?
Heel to toe (edge first).
138
What is a hone?
A natural sharpening stone or hard grinding surface for sharpening knives.
139
What are the types of microtomes mentioned?
1. Sliding microtome
2. Rotary microtome
3. Rocking microtome
4. Freezing microtome
5. Ultrathin microtome
140
What is a sliding microtome used for?
Cutting celloidin embedded sections.
141
What is the most popular type of microtome?
Rotary microtome.
142
What is the purpose of a freezing microtome?
For cutting unembedded frozen sections.
143
What are the types of hones?
1. Carborundum hone
2. Arkansas stone
3. Yellow Belgian/Belgium hone
144
What is stropping?
The process of removing debris from the knife edge and polishing it.
145
What is the direction used during stropping?
Toe to heel (edge last).
146
What is the purpose of a floating-out bath?
To flatten sections and visualize folds and creases in sections.
147
What is a cryostat used for?
For rapid preparation of urgent tissue biopsies and fluorescent antibody staining techniques.
148
What are the two methods widely used for staining cryostat sections?
1. H&E staining technique
2. Polychrome methylene blue.
149
What are frozen sections used for?
Rapid diagnosis of tissue and demonstration of lipids and nervous tissue elements.
150
What are common methods of freezing for frozen sections?
1. Liquid nitrogen
2. Isopentane cooled by liquid nitrogen
3. Carbon dioxide gas
4. Aerosol sprays.
151
What is freeze drying?
Preserving tissues by rapid freezing and removing water without chemical fixatives.
152
What is the advantage of freeze drying?
Produces minimum shrinkage and allows tissues to be processed in a fresh state.
153
What is freeze substitution?
A process similar to freeze-drying but involves fixing tissues before dehydration.
154
What is Rossman's fluid composed of?
Saturated Picric acid and Formaldehyde.
