Microtomy: Paraffin and frozen

7 Microtomy

Paraffin and frozen


Microtomy is the means by which tissue is sectioned and attached to a surface for further microscopic examination. Most microtomy is performed on paraffin wax embedded tissue blocks. The basic instrument used in microtomy is the microtome; an advancing mechanism moves the object (paraffin block) for a predetermined distance until it is in contact with the cutting tool (knife or blade). The specimen moves vertically past the cutting surface and a tissue section is produced. Good technique is achieved through ongoing practice.

Types of microtome

There are several types of microtome, each designed for a specific purpose, although many have multifunctional roles.

Microtome knives

There are many shapes, sizes and materials for microtome knives. Knives were developed to fit specific types of microtome, and to cope with different degrees of hardness of tissues and embedding media. Most steel knives have been replaced with disposal blades, although exceptions include the tool-edge knives for resin, and steel knives for some cryostats.

Paraffin section cutting

Equipment required

Tools needed for microtomy:

Section adhesives

Provided clean slides are used and sections are adequately dried, the problem of sections detaching from the slide during staining should not occur. There are occasions when sections may detach from the slide:

Adhesives may alleviate the problem of tissue loss. Protein adhesives such as albumen, gelatin and starch may be prone to bacterial growth or heavy staining; close monitoring will prevent these problems. Adhesives that may be used:

Practical microtomy

The expertise that must be gained to become a competent microtomist cannot be achieved from textbooks. Practical experience under the guidance of a skilled tutor is the best way to gain the confidence and coordination necessary to manipulate the microtome and the sections produced. Techniques will be described, providing information and helpful hints for use during microscopy.


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Dec 13, 2017 | Posted by in HISTOLOGY | Comments Off on Microtomy: Paraffin and frozen

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