Histology

A stained histologic specimen, sandwiched between a glass microscope slide and coverslip, mounted on the stage of a light microscope.
Microscopic view of a histologic specimen of human lung tissue stained with haematoxylin and eosin.
Masson's trichrome stain of rat airway. Connective tissue is stained blue, nuclei are stained dark red/purple, and cytoplasm is stained red/pink.
Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum by Santiago Ramón y Cajal, 1899. Instituto Santiago Ramón y Cajal, Madrid, Spain
histological section of human skin prepared for direct immunofluorescence using an anti-IgA antibody. IgA deposits are in the walls of small superficial capillaries (yellow arrows). The pale wavy green area on top is the epidermis, the bottom fibrous area is the dermis.


Histology is the study of the microscopic anatomy of cells and tissues of plants and animals, particularly the tissues. It is a part of cytology, and an essential tool of biology and medicine.

Histology is usually done by looking at cells and tissues under a light microscope or electron microscope. The tissue has to be specially prepared beforehand.

The process

The stages below are only described in outline. Laboratories which do histology work from schedules which are much more detailed.

Fixing

Chemical fixatives are used to preserve tissue from decay. This preserves the structure of the cell and of sub-cellular components such as cell organelles (e.g., nucleus, endoplasmic reticulum, mitochondria). The most common fixative for light microscopy is formalin (4% formaldehyde in saline).

Embedding

After fixing, the block of tissue is embedded in paraffin wax. This holds and preserves the tissue as a block.

Sectioning

The section is cut into a series of wafer-thin slices, each of which is put on a glass microscope slide. The machine which cuts the block is a mechanical guillotine which can be set to cut at a suitable depth for the tissue in question.

Staining

Stains are dyes, chemicals used to make cells and tissues easy to see under a microscope. There are many tissue stains, and each of them has advantages and disadvantages.

Haematoxylin and eosin (H&E)

This is the most widely used stain in biology and medicine. Haematoxylin colours cell nuclei and eosin colours cell cytoplasm.

Silver nitrate

Camillo Golgi developed a silver nitrate stain for nerve cells. His idea was used by Santiago Ramón y Cajal in his famous work on the structure of brain tissue.

Other Languages
Afrikaans: Histologie
العربية: علم الأنسجة
aragonés: Histolochía
asturianu: Histoloxía
azərbaycanca: Histologiya
تۆرکجه: هیستولوژی
Bân-lâm-gú: Cho͘-chit-ha̍k
беларуская: Гісталогія
български: Хистология
bosanski: Histologija
català: Histologia
čeština: Histologie
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Ελληνικά: Ιστολογία
English: Histology
español: Histología
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galego: Histoloxía
한국어: 조직학
hrvatski: Histologija
Bahasa Indonesia: Histologi
interlingua: Histologia
italiano: Istologia
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қазақша: Гистология
Kiswahili: Histolojia
Кыргызча: Гистология
Latina: Histologia
latviešu: Histoloģija
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magyar: Szövettan
македонски: Хистологија
მარგალური: ჰისტოლოგია
Bahasa Melayu: Histologi
Nederlands: Histologie
日本語: 組織学
norsk: Histologi
norsk nynorsk: Histologi
occitan: Istologia
polski: Histologia
português: Histologia
română: Histologie
русский: Гистология
Scots: Histology
slovenčina: Histológia
slovenščina: Histologija
српски / srpski: Хистологија
srpskohrvatski / српскохрватски: Histologija
suomi: Histologia
svenska: Histologi
Tagalog: Histolohiya
татарча/tatarça: Гистология
Türkçe: Doku bilimi
українська: Гістологія
اردو: نسیجیات
Tiếng Việt: Mô học
Winaray: Histolohiya
中文: 组织学