HT Microtomy & Staining 2 — Questions and Answers
Question 1: Which microtome component is adjusted to control section thickness?
- Coarse advance wheel
- Micrometer handwheel (Correct answer)
- Retraction mechanism
- Anti-roll plate
Correct answer: Micrometer handwheel
The micrometer handwheel on a rotary microtome controls the precise thickness advance per cutting stroke.
Question 2: A section shows a 'venetian blind' artifact with alternating thick and thin bands. What is the most likely cause?
- Dull knife edge
- Vibrating knife or block (Correct answer)
- Over-hardened tissue
- Inadequate clearing
Correct answer: Vibrating knife or block
Venetian blind artifact (chatter) is caused by vibration of the knife or block holder during cutting.
Question 3: What is the purpose of the anti-roll plate on a cryostat microtome?
- To prevent ice crystal formation
- To keep the section flat as it is cut (Correct answer)
- To control section thickness
- To cool the knife blade
Correct answer: To keep the section flat as it is cut
The anti-roll plate holds the section flat as it exits the knife edge, preventing it from curling.
Question 4: Masson's trichrome stain differentiates collagen from muscle using which color combination?
- Collagen blue/green, muscle red (Correct answer)
- Collagen red, muscle blue
- Collagen yellow, muscle purple
- Collagen black, muscle pink
Correct answer: Collagen blue/green, muscle red
In Masson's trichrome, collagen stains blue or green while muscle fibers stain red.
Question 5: Which stain is used specifically to demonstrate amyloid deposits in tissue sections?
- Alcian blue
- Congo red (Correct answer)
- Periodic acid-Schiff
- Toluidine blue
Correct answer: Congo red
Congo red stains amyloid deposits orange-red and shows apple-green birefringence under polarized light.
Question 6: What is the optimal cryostat cabinet temperature range for cutting most tissue sections?
- -5°C to -10°C
- -15°C to -25°C (Correct answer)
- -30°C to -40°C
- 0°C to -5°C
Correct answer: -15°C to -25°C
Most tissues cut best at cryostat temperatures between -15°C and -25°C, balancing tissue hardness and section quality.
Question 7: In the H&E stain, what cellular component is specifically targeted by the hematoxylin component?
- Cytoplasmic proteins
- Nucleic acids (DNA/RNA) (Correct answer)
- Lipids
- Carbohydrates
Correct answer: Nucleic acids (DNA/RNA)
Hematoxylin binds to nucleic acids (DNA and RNA) in the nucleus and cytoplasm, staining them blue-purple.
HT Microtomy & Staining 2
Which microtome component is adjusted to control section thickness?