Histology and Its Methods of Study

Objectives: Upon completion of this lecture, the student should be able to:
• Explain the main steps of tissue preparations.
• Describe the important of each step in tissue processing.
• Describe the H&E staining procedure

Histology: is the study of the tissues of the body and how these tissues are arranged to constitute organs. Tissues are made of two interacting components: cells and extracellular matrix. The main functions of extracellular matrix are:
1- Provide a mechanical support for the cells,
2- Transport nutrients to the cells,
3- Carry away catabolites and secretory products.
Cells produce the extracellular matrix, but it also influenced and sometimes controlled by molecules of the matrix. Many components of the matrix recognized by and attaching to receptors present on cell surfaces which are molecules that cross the cell membranes and connect to structural components of the intracellular cytoplasm. Each of the fundamental tissues (except the central nervous system) is formed by several types of cells and typically by specific associations of cells and extracellular matrix.

Preparation of Tissues for Study
It is the preparation of histological sections or tissue slices that can be studied with the aid of the light microscope. They must be sectioned to obtain thin, translucent sections and then attached to glass slides before they can be examined. The ideal microscope tissue preparation should be preserved so that the tissue on the slide has the same structure and molecular composition as it had in the body.