This laboratory is concerned with the identification of the cells and cellular organelles utilizing images from the light and electron microscopes.

Stains commonly used in histology for studying cells and tissues at the light microscopic level include hematoxylin and eosin, usually referred to as H & E. Hematoxylin is a basic stain that preferentially colors acidic components of the cell blue to black. Common acidic components of the cell include DNA and RNA. Since the acidic components of the cell “attract” basic stains, they are said to be basophilic. Eosin is an acid dye that stains the basic components of the cell pink. Because many cytoplasmic constituents have a basic pH, regions of the cytoplasm stain pink. The cytoplasmic components that have a basic pH are said to be acidophilic.