Cytological Techniques

Cytological Techniques

1. Preparation of Slides

There are different types of mounting based on the portion of a specimen to be observed

a. Whole mount: The whole organism or smaller structure is mounted over a slide and observed.

b. Squash: Is a preparation where the ­material to be observed is crushed/ squashed on to a slide so as to reveal their contents. Example: Pollen grains, mitosis and meiosis in root tips and flower buds to observe chromosomes.

c. Smears: Here the specimen is in the fluid (blood, microbial cultures etc.,) are scraped, brushed or aspirated from surface of organ. Example: Epithelial cells.

d. Sections: Free hand sections from a specimen and thin sections are selected, stained and mounted on a slide. Example: Leaf and stem of plants.

2. Recording the Observations

The observations made through a microscope can be recorded by hand diagrams or through microphotographs.

Hand diagrams: Hand diagrams are drawn using ordinary pencil by observing the slide and drawing manually.

Microphotograph: Images of structures observed through microscopes can be further magnified, projected and saved by attaching a camera to the microscope by a microscope coupler or eyepiece adaptor. Picture taken using a inbuilt camera in a microscope is called microphotography or microphotograph.

3. Staining Techniques

Stainingisveryimportanttoobservedifferent components of the cell. Each component of the cell has different affinity towards different stains. The technique of staining the cells and tissue is called ‘histochemical staining’ or ‘histochemistry’.

Common stains used in Histochemistry