Protistiary - Left Right in Sections 3

Left right in sections 3 - orientation issues 3
Sections are cut on a microtome . The process is called microtomy. We can exercise some control when sections are taken. The block is usually trimmed into a trapezium, and the sections consequently are parallelograms as the diagram to the left shows. The broad side is where the slice begins; the narrow end is where the section ends. This organization helps to push the last section away from the edge of the knife and allow a ribbon of sections to be made. Such ribbons are needed if we wish to reconstruct shapes from a series of sections - and parts of series, packed into three rows on a grid, are shown in the micrograph to the right.
If we trim the block so that it is not asymmetrical, we will be able to see the asymmetry in the ribbon of sections. Unfortunately, it remains possible to invert the grid and lose the information. In the end, it is more helpful to call upon inherent asymmetries of the organism or of organelles.
protistiary home page top of electron microscopy exercise

Sections are cut on a microtome . The process is called microtomy.

We can exercise some control when sections are taken. The block is usually trimmed into a trapezium, and the sections consequently are parallelograms as the diagram to the left shows. The broad side is where the slice begins; the narrow end is where the section ends. This organization helps to push the last section away from the edge of the knife and allow a ribbon of sections to be made. Such ribbons are needed if we wish to reconstruct shapes from a series of sections - and parts of series, packed into three rows on a grid, are shown in the micrograph to the right.