Study of the tissues of the body and how these tissues are arranged to constitute organs. Not only tissues but also that of cells, organs and system.

The Greek root histo can be translated as either

Involves all aspects of tissue biology, with the focus on how cells’ structure and arrangement optimize functions specific to each organ.

Organization of the Body

A method of preparation of tissue for microscopic examination

PREPARATION OF TISSUES FOR STUDY

Histotechniques

Prior grossing sample must be

Submerging the specimen in chemical substances in order to PRESERVE THE TISSUE.

Immersing the tissue in increasing concentration of alcohol to REMOVE WATER from the tissue.

Since alcohol is insoluble with paraffin, it must be replaced by a clearing agent so that I can be IMPREGNATED WITH PARAFFIN WAX.

Removal of clearing agent. Its purpose is TO FILL THE TISSUE GAP with a solid medium (wax)

Placing the tissue in paraffin blocks. Paraffin penetrates all intercellular spaces and even into the cells making the tissue MORE RESISTANT TO SECTIONING.

CUTTING OF TISSUE by use of MICROTOME about 3-5 u in thickness. The cut tissue, paraffin ribbon are placed in a basin of water.

Stains that differentiate acidic and basic components of the cell. Stains that differentiate fibrous component of the matrix. Metallic salts that precipitate tissue forming metal deposits on them.

MOST COMMONLY USED STAINING PROCEDURE

Stains basophilic tissue components

Stains acidophilic tissue components

Basic Dyes

Acidic dyes

Placing a cover slip with a few drops of CANADA BALSAM as a mounting medium on processed tissue.

Label the organ on the prepared slides.

Staining

ELASTIC STAIN

RETICULAR FIBERS

STRIATION OF MUSCLES, NUCLEI, ERYTHROCYTES

Glycogen, carbohydrate-rich molecules

Differential staining of blood cells