The word “histology” came from the Greek word “histo” meaning tissue and “logia” meaning science. Histology is a term that refers to the study of the microscopic anatomy of tissues and cells using special staining techniques combined with light and electron microscopy.
There are 4 main steps for the preparation of slides for microscopic examination:
The purpose of fixation is to preserve the tissue and slow down tissue degradation. Keep tissues permanently in as life-like a state as possible.
Tissue processing is to take animal or human tissue from fixation to the state where it is completely infiltrated with a suitable histological wax, paraffin. Then tissue can be embedded in paraffin to be formed into a “block” which can be clamped into a microtome for section cutting.
Sectioning is the process of cutting thin slices of a sample from an embedding block. This is done with a microtome. The sections are usually on the order of 4-10 µm thick for use with light microscopy. Following sectioning, samples are placed on glass slides.
The purpose of staining is to identify different tissue components through the color reactions.