Histochemistry

This page answers the question "What is histochemistry ?".

Definition of Histochemistry

Histochemistry is the study of the identification and distribution of chemical compounds within and between biological cells using histological techniques such as histology stains, indicators and light (optical) and electron microscopy.

An even shorter definition is:

Histochemistry is the aspect of histology concerned with the identification of chemical components in biological cells and tissues.

In order to fully understand these definitions of histochemistry, it may help to recall the definitions of histology and chemistry.

Definition of Histology:	Definition of Chemistry:
Histology is the microscopic study of the structure of biological cells and tissues using special techniques incl. histology stains, combined with light and electron microscopy.	Chemistry is the science of matter and the changes that occur between different kinds of matter, especially chemical reactions, during which types of matter are re-arranged into other types of matter e.g. liquid water splitting into the gases hydrogen and oxygen.

So, whereas histology in general is the study of biological cells and tissues in fine microscopic detail using special histological techniques, histochemistry is concerned specifically with the chemicals within, between, and forming the biological cells and tissues themselves.

Compare Histochemistry with Biochemistry

• Biochemistry is the study of chemical processes in living organisms (including plants and animals).
• Histochemistry is the identification and study of chemicals within and around the microstructure of biological cells and tissues observed using particular techniques to prepare histological specimens and microscopes to observe those specimens.

Related Terms and Specialist disciplines within Histochemistry

Histochemistry may seem like an extremely specialist area. Medical sciences such as biochemistry and histochemistry have become so advanced that there are even more sub-disiplines within already specialist-seeming areas such as histochemistry. Those subjects are not usually included in school or college-level courses or discussed at the level of introductory biology but they may be of interest to students reading further around scientific subjects to decide which topics to pursue at more advanced levels.

• Cytochemistry - the study of the actions of chemical compounds within living (biological) cells.
• Immunohistochemistry - the process of detecting antigens in sections of intact biological tissue (i.e. biological tissues in which each cell is surrounded by the tissue structures and other cells normally found in the intact tissue) using the principle of antibodies binding specifically to antigens in biological tissues.
• Immunocytochemistry - the process of using antibodies that target specific peptides or protein antigens in cells such that the bound antibodies can then be detected using various methods.
  Note: Immunocytochemistry is different from immunohistochemistry because in the case of immunocytochemistry the tissues studied have had most or all of their surrounding extracellular matrix removed. This means that immunocytochemistry can be used to study cells that have been grown within a culture, deposited from suspension, or taken from a smear.

See also What is Histology ?, Histology Stains, How to prepare Histology Slides, Histopathology, the Structure of a Cell, and the Diagram of Mitosis.