Microtome in Microscopy

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Questions and Answers

What is the main purpose of a microtome?

To slice hard materials like bone and plant matter

To observe samples under transmitted light

To cut extremely thin slices of material for observation (correct)

To prepare samples for electron radiation

What type of blade is used to slice hard materials like bone and plant matter?

Glass knives

Ceramic knives

Diamond knives (correct)

Steel blades

What is the typical thickness range of microtome sections?

Between 50 nm and 100 μm (correct)

Between 1 nm and 100 nm

Between 1 mm and 10 mm

Between 1 μm and 1 cm

What is the earliest form of microtomy?

Freehand sectioning of fresh or fixed material using a sharp razor Signup and view all the answers

What is the typical application of a sledge microtome?

Preparing large samples embedded in paraffin for biological preparations Signup and view all the answers

What is the typical cut thickness achievable on a rotary microtome?

Between 1 and 60 μm Signup and view all the answers

What type of microtome is used to prepare thin sections for materials like bones, minerals, and teeth?

Rotary microtome Signup and view all the answers

How many types of microtomes are mentioned in the content?

9 Signup and view all the answers

What is the minimum thickness of a section that can be cut using a sledge microtome?

0.5 μm Signup and view all the answers

What is the purpose of a cryomicrotome setup?

To reduce the sample temperature and increase the hardness of the sample Signup and view all the answers

What is the typical thickness of sections cut using an ultramicrotome?

40-100 nm Signup and view all the answers

What is the advantage of using a vibrating microtome?

It requires less pressure to cut the sample Signup and view all the answers

What type of microtome is suitable for cutting hard materials such as teeth or bones?

Saw microtome Signup and view all the answers

What is the advantage of using a laser microtome?

It allows for contact-free slicing of the sample Signup and view all the answers

What is the typical range of thickness for sections cut using a vibrating microtome?

30-500 μm Signup and view all the answers

What is the minimum thickness of a section that can be cut using a saw microtome?

30 μm Signup and view all the answers

Study Notes

Microtome

A microtome is a device used to cut extremely thin slices of material, known as sections, which is important in science.
Microtomes are used in microscopy to prepare samples for observation under transmitted light or electron radiation.
The device uses steel, glass, or diamond blades, depending on the specimen being sliced and the desired thickness of the sections being cut.

Types of Blades

Steel blades are used to prepare sections of animal or plant tissues for light microscopy histology.
Glass knives are used to slice sections for light microscopy and to slice very thin sections for electron microscopy.
Diamond knives are used to slice hard materials such as bone, teeth, and plant matter for both light microscopy and electron microscopy.

Microtomy

Microtomy is used to prepare thin sections for materials such as bones, minerals, and teeth.
Microtome sections can be made thin enough to section a human hair across its breadth, with section thickness between 50 nm and 100 μm.

History of Microtomy

The earliest form of microtomy was the freehand sectioning of fresh or fixed material using a sharp razor.

Types of Microtomes

There are several types of microtomes, including:
- Rocking microtome
- Rotary rocking microtome
- Sledge microtome
- Rotary microtome
- Cryomicrotome
- Ultramicrotome
- Vibrating microtome
- Saw microtome
- Laser microtome

Sledge Microtome

Typical applications for this design of microtome are for the preparation of large samples, such as those embedded in paraffin for biological preparations.
Typical cut thickness achievable on a sledge microtome is between 1 and 60 μm.

Rotary Microtome

The typical cut thickness for a rotary microtome is between 1 and 60 μm.
For hard materials, such as a sample embedded in a synthetic resin, this design of microtome can allow good "semi-thin" sections with a thickness of as low as 0.5 μm.

Cryomicrotome

For the cutting of frozen samples, many rotary microtomes can be adapted to cut in a liquid-nitrogen chamber, in a so-called cryomicrotome setup.
The reduced temperature allows the hardness of the sample to be increased, which allows the preparation of semi-thin samples.

Ultramicrotome

It allows the preparation of extremely thin sections, with a typical thickness of between 40 and 100 nm for transmission electron microscopy.
Diamond knives (preferably) and glass knives are used with ultramicrotomes.
To collect the sections, they are floated on top of a liquid as they are cut and are carefully picked up onto grids suitable for TEM specimen viewing.

Vibrating Microtome

The vibrating microtome operates by cutting using a vibrating blade, allowing the resultant cut to be made with less pressure than would be required for a stationary blade.
The vibrating microtome is usually used for difficult biological samples.
The cut thickness is usually around 30–500 μm for live tissue and 10–500 μm for fixed tissue.

Saw Microtome

The saw microtome is especially used for hard materials such as teeth or bones.
The microtome of this type has a recessed rotating saw, which slices through the sample.
The minimal cut thickness is approximately 30 μm and can be made for comparatively large samples.

Laser Microtome

The laser microtome uses contact-free slicing and does not require prior preparation of the sample.
It can also be used for very hard materials, such as bones or teeth, as well as some ceramics.
The typical thickness of the cuts made by a laser microtome is between 10-100 μm.