40 Questions
What are the two types of block advancement mechanisms?
Retracting and non retracting
What does a retracting action do on the upstroke?
Moves the tissue block away from the knife
What is produced by a retracting action on the tissue block?
A flat face
During which movement does the retracting action occur?
Upstroke
What is not involved in the mechanism of block advancement?
Rotating action
What is another name for the rotary microtome?
Minot microtome
Who invented the rotary microtome?
Professor Minot
How widely used is the rotary microtome?
Most widely used
What is the popularity of the rotary microtome design?
Very popular
Which description best fits the rotary microtome?
Most widely used and very popular design
What is the purpose of the hand wheel in the mechanism?
To move the specimen vertically past the cutting surface
What does the block holder move on?
A steel carriage
How is the block holder advanced?
By a micrometer screw
What type of sections does the mechanism cut?
Flat sections
What action does the hand wheel perform?
Returns the specimen to the starting position
Which type of rotary microtome is completely manipulated by the operator?
Manual
What thickness range can a semi-automated microtome cut?
0.5 to 2.0 um
How many motors does a fully automated rotary microtome have?
Two motors
Which type of rotary microtome includes foot and hand control?
Semi-automated
Which of the following is an example of a fully automated rotary microtome?
Automated cryostate
What is the function of the microtome base plate?
It secures the knife holder base.
Which component of the microtome must be stationary and locked during microtomy?
Knife holder base
Which part of the knife holder adjusts the knife angle?
Knife tilt
What is the function of the face plate in the knife holder?
Guides the ribbons away from the blade
Which of the following holds the blade in the knife holder?
Blade clamp
What is the role of a cassette clamp or block holder?
To hold the paraffin block in place
What movement does the cassette clamp or block holder perform with each revolution?
Moves the block holder up and down
What feature may the cassette clamp or block holder have to help align the tissue with the blade?
Knobs for manipulation
What is the function of the coarse hand wheel?
To move the block holder either towards or away from the knife
Which part remains stationary while the cassette clamp or block holder moves up and down?
The blade
What does the advancement hand wheel do?
Advances the block toward the knife
What feature prevents the block holder from coming down towards the blade?
Safety lock
When should the safety lock be used on a rotary microtome?
When inserting or removing a block
In which direction does the advancement hand wheel turn?
Clockwise
What is the primary purpose of the advancement hand wheel's safety lock?
To prevent accidental movement
What is the range of micron settings for section thickness on most microtomes?
1 to 60 microns
What does the thickness gauge measure on a microtome?
Section thickness
Which part of the microtome allows for micron adjustment?
Thickness gauge
Where does the whole microtome rest?
Base
What is another term for the thickness gauge on a microtome?
Micron adjustment
Study Notes
Rotary Microtome
- Most widely used microtome, also known as the Minot microtome, after its inventor Professor.
- Popular design used globally.
Mechanism
- Hand wheel rotates 360 degrees, moving the specimen vertically past the cutting surface (knife edge) and returning to the starting position.
- Block holder mounted on a steel carriage moves up and down in grooves, advanced by a micrometer screw, cutting perfectly flat sections.
Types of Rotary Microtome
- Manual: Completely operated by the operator.
- Semi-automated: Has a built-in motor drive with foot and hand control, can cut thin sections of 0.5 to 2.0 um thickness with suitable accessories.
- Fully automated: Has two motors driving both the fine and coarse advance hand-wheels, an example is the automated cryostate.
Mechanism of Block Advancement
- Retracting or non-retracting action.
- Retracting action moves the tissue block away from the knife on upstroke, producing a flat face to the tissue block.
Rotary Microtome Parts
- Microtome base plate or stage: Platform with rails that secure the knife holder base.
- Knife holder base: Part that anchors the knife holder to the microtome stage, must be stationary and locked during microtomy.
Knife Holder Components
- Blade clamp: Holds the blade.
- Knife tilt: Adjusts the knife angle.
- Face plate: Guides the ribbons away from the blade and towards the operator.
Cassette Clamp or Block Holder
- Holds the paraffin block in place.
- Moves up and down with each revolution while the blade is stationary.
- May have knobs to manipulate the block face in various directions to align with the blade.
Coarse Hand Wheel
- Moves the block holder toward or away from the knife.
Advancement Hand Wheel
- Turns in one direction and advances the block toward the knife at specified microns.
- Equipped with a safety lock to prevent the wheel from releasing and having the block holder come down towards the blade when not actively sectioning.
Micron Adjustment
- Micron settings for section thickness range from 1 to 60 microns on most microtomes.
- Thickness Gauge: Micron settings for section thickness.
Base
- The base on which the whole microtome rests.
Learn about the different types of rotary microtomes, including manual, semi-automated, and fully automated microtomes, and their characteristics.
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