Frozen section

What is the main purpose of a frozen section during surgery? a) To preserve tissue for later examination
b) To provide rapid pathological diagnosis
c) To improve patient recovery time
d) To enhance tissue appearance
Answer: b

Which of the following is NOT an advantage of frozen section? a) Rapid processing time
b) Less equipment required
c) High morphological detail
d) Minimal ventilation needs
Answer: c

What is a major disadvantage of frozen section? a) Requires complex equipment
b) Takes longer than paraffin sectioning
c) Potential ice crystal artifacts
d) Cannot be used for lipid demonstration
Answer: c

Which tissue type is commonly examined using frozen section? a) Bone
b) Muscle and nerve
c) Cartilage
d) Blood
Answer: b

What freezing method is ideal for muscle tissue? a) Liquid nitrogen
b) Isopentane cooled by liquid nitrogen
c) Carbon dioxide gas
d) Aerosol sprays
Answer: b

Which temperature range is optimal for cryostat operation? a) -5°C to -10°C
b) -10°C to -15°C
c) -18°C to -20°C
d) -25°C to -30°C
Answer: c

What is the primary function of the cryostat? a) To freeze tissue for sectioning
b) To heat tissue before embedding
c) To store specimens at room temperature
d) To dehydrate tissue
Answer: a

In the cold knife procedure, what is applied to freeze the filter paper onto the microtome stage? a) Liquid nitrogen
b) Gum syrup
c) CO2 bursts
d) Isopentane
Answer: c

What is the typical thickness of frozen sections? a) 2-4 microns
b) 5-10 microns
c) 15-20 microns
d) 25-30 microns
Answer: b

Which embedding medium is commonly used in cryostat sectioning? a) Paraffin wax
b) Epoxy resin
c) OCT compound
d) Agar gel
Answer: c

What is the primary function of the antiroll plate in cryostat sectioning? a) Prevents ice crystal formation
b) Maintains tissue at low temperatures
c) Prevents curling of cut tissue
d) Facilitates tissue embedding
Answer: c

What is the ideal thickness for frozen tissue blocks before freezing? a) 1-2 mm
b) 3-5 mm
c) 6-8 mm
d) 10-12 mm
Answer: b

Which of the following is a rapid freezing method that minimizes ice crystal artifacts? a) Freeze-drying
b) Isopentane cooled by liquid nitrogen
c) Freeze-substitution
d) Room temperature drying
Answer: b

What is the main function of OCT compound? a) Fixes the tissue for sectioning
b) Acts as an embedding medium
c) Prevents ice formation
d) Removes artifacts
Answer: b

Which freezing method is the fastest but may cause cracking? a) Liquid nitrogen
b) Isopentane
c) Aerosol sprays
d) Carbon dioxide gas
Answer: a

What is the effect of slow freezing on tissue? a) Prevents distortion
b) Causes ice crystal formation
c) Enhances section quality
d) Prevents dehydration
Answer: b

The cryostat maintains isothermic conditions at: a) -5°C to -10°C
b) -10°C to -15°C
c) -18°C to -20°C
d) -25°C to -30°C
Answer: c

What is the purpose of freeze-drying in tissue preservation? a) Prevents chemical alteration
b) Speeds up staining
c) Prevents sectioning errors
d) Helps in lipid demonstration
Answer: a

What component of the cryostat moves the tissue via a rotary wheel? a) Blade holder
b) Tissue shelf
c) Rotary microtome
d) Antiroll plate
Answer: c

Which chemical is commonly used in freeze-substitution? a) Formalin
b) Osmium tetroxide
c) Acetone
d) Xylene
Answer: b

Which freezing artifact appears as holes in tissue sections? a) Compression artifacts
b) Ice crystal artifacts
c) Fixation artifacts
d) Sectioning artifacts
Answer: b

What happens if a frozen tissue section is not maintained in a solid state? a) It dehydrates quickly
b) It improves morphology
c) It increases section thickness
d) It reduces staining contrast
Answer: a

What is the function of the antiroll plate in cryostat sectioning? a) Reduces ice crystal formation
b) Prevents tissue curling
c) Maintains isothermic conditions
d) Fixes tissue onto slides
Answer: b

What is the purpose of freeze-substitution? a) Dehydrates tissue at low temperatures
b) Enhances tissue embedding
c) Fixes tissue using paraffin wax
d) Prevents tissue dehydration
Answer: a

What is an alternative to an antiroll plate for tissue handling? a) CO2 gas
b) Camel hair brush
c) Formalin fixation
d) Water bath
Answer: b

What is the main purpose of using an antiroll plate in cryostat sectioning? a) To heat the tissue block
b) To prevent curling of the tissue section
c) To increase the sectioning speed
d) To provide additional cooling
Answer: b

Which freezing method is suitable for small tissue pieces? a) Liquid nitrogen
b) Isopentane
c) Aerosol sprays
d) Carbon dioxide gas
Answer: c

Which of the following is a common fixative for frozen sections? a) 95% ethanol
b) Xylene
c) Acetone
d) Formaldehyde
Answer: c

What type of blade is typically used in cryostat sectioning? a) Serrated blade
b) High-profile disposable blade
c) Glass knife
d) Diamond knife
Answer: b

What is the ideal temperature range for freeze-drying tissue? a) -40°C to -60°C
b) -100°C to -120°C
c) -160°C to -180°C
d) -200°C to -220°C
Answer: c

What is the purpose of the rotary microtome in cryostat sectioning? a) To cool the specimen
b) To move the tissue for sectioning
c) To fix the tissue before sectioning
d) To embed the specimen in paraffin
Answer: b

What happens when frozen tissue is cut too slowly? a) The tissue remains intact
b) Ice crystal artifacts increase
c) The section becomes smoother
d) The section adheres better to the slide
Answer: b

Which of the following factors affects cryostat sectioning? a) Tissue temperature
b) Type of stain used
c) Length of tissue storage
d) Slide thickness
Answer: a

What is the main function of freeze-substitution? a) To remove lipids from the tissue
b) To replace water with a chemical fixative at low temperatures
c) To freeze the tissue at an extremely low temperature
d) To enhance staining properties
Answer: b

What fixative is commonly used for enzyme histochemistry in frozen sections? a) Formalin
b) 10% formol calcium
c) Acetone
d) Bouin’s solution
Answer: b

What is the primary drawback of freeze-drying? a) Causes excessive tissue shrinkage
b) Time-consuming and expensive
c) Requires specialized staining
d) Does not preserve cellular structure
Answer: b

What is the function of the specimen holder (chuck) in cryostat sectioning? a) Embeds the tissue in paraffin
b) Holds the tissue in place for cutting
c) Stains the tissue automatically
d) Prevents ice crystal formation
Answer: b

Which of the following is a key advantage of freeze-substitution over freeze-drying? a) Faster processing time
b) Requires no special equipment
c) More effective at preserving tissue structure
d) Produces higher contrast in staining
Answer: a

What happens if the knife in a cryostat is not properly chilled? a) Sections become thicker
b) Tissue melts during cutting
c) Ice crystals are eliminated
d) Staining is improved
Answer: b

Which of the following techniques is used to remove water from frozen tissue without chemical fixation? a) Freeze-drying
b) Freeze-substitution
c) Rapid freezing
d) Enzyme histochemistry
Answer: a

What is the primary reason for maintaining tissue in a frozen solid state during sectioning? a) To prevent compression and distortion
b) To enhance staining properties
c) To increase sectioning speed
d) To make tissue more flexible
Answer: a

Which of the following freezing artifacts is most problematic for skeletal muscle sections? a) Ice crystal formation
b) Tissue compression
c) Uneven freezing
d) Staining inconsistencies
Answer: a

What is the recommended thickness for cryostat sections? a) 1-3 µm
b) 5-10 µm
c) 15-20 µm
d) 25-30 µm
Answer: b

Why is fast freezing preferred over slow freezing? a) It prevents enzymatic degradation
b) It reduces ice crystal formation
c) It speeds up staining
d) It makes sectioning easier
Answer: b

What type of stains are commonly used for frozen section diagnosis? a) Hematoxylin and eosin (H&E)
b) Periodic acid-Schiff (PAS)
c) Masson's trichrome
d) All of the above
Answer: d

What is the primary disadvantage of using liquid nitrogen for freezing? a) Causes cracking of tissue
b) Requires a long freezing time
c) Does not work for muscle tissue
d) Leads to tissue dehydration
Answer: a

Which step follows section cutting in frozen section preparation? a) Fixation
b) Mounting
c) Staining
d) All of the above
Answer: d

What is the role of the antiroll plate in sectioning? a) Ensures uniform section thickness
b) Prevents tissue curling
c) Heats tissue before sectioning
d) Improves freezing efficiency
Answer: b

Which of the following best describes freeze-drying? a) Removes water from tissue through sublimation
b) Uses acetone for dehydration
c) Fixes tissue using formalin
d) Enhances staining contrast
Answer: a

What temperature should a cryostat chamber be maintained at for optimal sectioning? a) -5°C to -10°C
b) -10°C to -15°C
c) -18°C to -20°C
d) -25°C to -30°C
Answer: c

Which of the following freezing methods is ideal for neuropathology? a) Liquid nitrogen
b) Freeze-drying
c) Freeze-substitution
d) Isopentane
Answer: c

What type of artifact can occur due to uneven freezing with liquid nitrogen? a) Ice crystal formation
b) Tissue dehydration
c) Increased staining contrast
d) Tissue shrinkage
Answer: a

What is the function of the cryostat chamber in frozen section processing? a) To maintain low temperatures for sectioning
b) To embed tissues in paraffin
c) To remove artifacts before staining
d) To replace tissue water with fixatives
Answer: a

Why are frozen sections preferred over paraffin sections for certain studies? a) They provide better long-term preservation
b) They allow for rapid intraoperative diagnosis
c) They eliminate the need for staining
d) They require less tissue preparation
Answer: b

What should be done if tissue is stored in alcohol before frozen sectioning? a) Freeze the tissue immediately
b) Wash the tissue in water for 12-24 hours before freezing
c) Stain the tissue before freezing
d) Embed the tissue in paraffin
Answer: b