Histology is the study of the structure and function of microscopic anatomy of plants and animals. Microscopic anatomy includes the cells, tissues, organs and organ system of an organism. These studies are performed especially by examining cells and tissues. First particular part of an organ is selected. Then staining is done followed by an examination under a light or electron microscope. Microscopes are the basic tools used in the histological studies. Histological stains are very important as they enhance the ability of visualizing and differentiating of microscopic structures.
Cytology is the study of structure, function and chemistry of cells. It is a branch of biology which deals directly with the structural and functional organization of cells and also with the other phenomena such as metabolism, ontogenetic differentiation, heredity, and phylogeny.
• In cytology, we go only for cellular level, but in histology, we mainly examine the tissue architecture of a particular tissue.
• The study of cellular structure and function is called cytology, while the study of cells and tissues in an organism is called histology.
• The costs for histological studies are higher than cytology.
• In cytology, it mainly aims the cells. Therefore, the cytological observations have excellent cellular details unlike in the histological observations.
• Tissue details are present only in histology while details of tissue architecture cannot be observed in cytology.