FACTOID # 16: In the 2000 Presidential Election, Texas gave Ralph Nader the 3rd highest popular vote count of any US state.
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 


FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:



(* = Graphable)



Encyclopedia > Histologic
A thin section of lung tissue stained with hematoxylin and eosin. This individual suffers from emphysema.
A thin section of lung tissue stained with hematoxylin and eosin. This individual suffers from emphysema.

Histology is the study of tissue sectioned as a thin slice, using a microscope. It can be described as microscopic anatomy. Histology is an essential tool of biology. Histopathology, the microscopic study of diseased tissue, is an important tool of anatomical pathology since accurate diagnosis of tumors and other diseases usually requires histopathological examination of samples. The trained technicians who perform the work of processing, thin sectioning, and staining these tissues are Histologic Technicians (HT) and Histologic Technologists (HTL). Their field of study is called histotechnology. Image File history File links Image is of H&E (haematoxylin and eosin) stained lung tissue sample taken from an end-stage emphysema patient. ... Image File history File links Image is of H&E (haematoxylin and eosin) stained lung tissue sample taken from an end-stage emphysema patient. ... The lungs flank the heart and great vessels in the chest cavity. ... Haematoxylin is extracted from the wood of the logwood tree. ... Eosin is an orange-pink dye derived from coal tar. ... Biological tissue is a substance made up of cells that perform a similar function. ... 1852 microscope Compound microscope made by John Cuff in 1750 A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... Anatomical drawing of the human muscles from the Encyclopédie. ... Main articles: Life The most salient example of biological universality is that all living things share a common carbon-based biochemistry and in particular pass on their characteristics via genetic material, which is based on nucleic acids such as DNA and which uses a common genetic code with only minor... Histopathology is the microscopic study of diseased tissue. ... Anatomical pathology is the branch of pathology that is concerned with the diagnosis of disease based on the gross and microscopic examination of cells and tissues. ...

Histological examination of tissues starts with surgery, biopsy or autopsy. The tissues are then fixed in a fixative, a process that stabilizes the tissues to prevent decay. The most common fixative is formalin (10% formaldehyde in water). The samples are then immersed in multiple baths of progressively more concentrated ethanol, to dehydrate the tissue, followed by a clearing agent such as chloroform, xylene or Histoclear, and finally hot molten paraffin wax (impregnation). During this 12 to 16 hour process, paraffin wax will replace the water: soft, moist tissues are turned into a hard paraffin block, which is then placed in a mould containing more molten wax (embedded) and allowed to cool and harden. This allows the sectioning of tissues into very thin (5 - 7 micrometer) sections using a microtome. These slices, thinner than the average cell, are then placed on a glass slide for staining. A typical modern surgery operation For other meanings of the word, see Surgery (disambiguation) Surgery (from the Greek cheirourgia meaning hand work) is the medical specialty that treats diseases or injuries by operative manual and instrumental treatment. ... A biopsy (in Greek: bios = life and opsy = look/appearance) is a medical test involving the removal of cells or tissues for examination. ... An autopsy, also known as a post-mortem examination or an obduction, is a medical procedure that consists of a thorough examination of a corpse to determine the cause and manner of a persons death and to evaluate any disease or injury that may be present. ... The chemical compound formaldehyde (also known as methanal), is a gas with a strong pungent smell. ... Ethanol, also known as ethyl alcohol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ... PEL-TWA (OSHA) 50 ppm (240 mg/m3) IDLH (NIOSH) 500 ppm Flash point non-flammable RTECS number FS9100000 Supplementary data page Structure & properties n, εr, etc. ... The term xylenes refers to a group of 3 benzene derivatives which encompasses ortho-, meta-, and para- isomers of dimethyl benzene. ... Paraffin is a common name for a group of high molecular weight alkane hydrocarbons with the general formula CnH2n+2, where n is greater than about 20. ... A microtome is a mechanical instrument used to cut very thin slices for microscopic examination. ... Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, and are sometimes called the building blocks of life. ... ...

A 5 to 7 micrometer slice of most tissues is almost completely transparent with very little visible detail. To see the tissue under a microscope, the sections are stained with one or more pigments. Hematoxylin and eosin are among the most commonly used stains in histology and histopathology. Hematoxylin colors nuclei blue, eosin colors the cytoplasm pink. Other compound used to color tissue sections include saffron, silver salts and numerous natural and artificial dyes originally developed to stain cloth fibers. The science of tissue staining is called histochemistry. 1852 microscope Compound microscope made by John Cuff in 1750 A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... ... Haematoxylin is extracted from the wood of the logwood tree. ... Eosin is an orange-pink dye derived from coal tar. ... Plural: nuclei In chemistry and physics, the nucleus (atomic nucleus) is the collection of protons and neutrons in the center of an atom that carries the bulk of the atoms mass and positive charge. ... Cytoplasm is a homogeneous, generally clear jelly-like material that fills cells. ... Saffron is the name given to the dried stigma and part of the style of the saffron crocus, traditionally called Crocus sativus, which are harvested, dried, and used for cooking. ... A dye can generally be described as a coloured substance that has an affinity to the substrate to which it is being applied. ...

Recently, antibodies are used to stain specific proteins: this is called immunohistochemistry. This technique has greatly increased the ability to identify categories of cells under a microscope. Other advanced techniques include in situ hybridization to identify specific DNA or RNA molecules, and confocal microscopy. Digital cameras are increasingly used to capture histological and histopathological images. Wikipedia does not yet have an article with this exact name. ... A SiPix digital camera next to a matchbox to show scale. ...

In the 19th Century, histology was an academic discipline in its own right. The 1906 Nobel Prize in Physiology or Medicine was awarded to two histologists, Camillo Golgi and Santiago Ramón y Cajal. They had dueling interpretations of the neural structure of the brain based in differing interpretations of the same images. Sir Edward Appletons medal Photographs of Nobel Prize Medals. ... Camillo Golgi Camillo Golgi (July 7, 1843 – January 21, 1926) was an Italian physician. ... Santiago Ramón y Cajal Santiago Ramón y Cajal (May 1, 1852 – October 17, 1934), Nobel laureate, 1906, was a Spanish histologist and is considered to be the father of modern neuroscience. ...


Histological classification of animal tissues

  • epithelium: the lining of glands, bowel, skin and some organs like the liver, lung, kidney,
  • endothelium: the lining of blood and lymphatic vessels,
  • mesothelium: the lining of pleural, peritoneal and pericardial spaces,
  • mesenchyme: the cells filling the spaces between the organs, including fat, muscle, bone, cartilage and tendon cells,
  • blood cells: the red and white blood cells, including those found in lymph nodes and spleen,
  • neurons: cells forming the brain, nerves and some glands like the pituitary and adrenal glands,
  • germ cells: reproductive cells, spermatozoa in men, oocytes in women,
  • placenta: a specialized organ essential for the growth of the fetus in the mother's uterus, and
  • stem cells: cells able to turn into one or several of the above types.

Note that tissues from plant, fungus and microorganisms can also be examined histologically. Their structure is very different from animal tissue. In zootomy, epithelium is a tissue composed of a layer of cells. ... The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... The mesothelium is a membrane that forms the lining of several body cavities: the pleura (thoracal cavity), peritoneum (abdominal cavity) and pericardium (heart sac). ... Mesenchyme (also known as embryonic connective tissue) is the mass of tissue that develops mainly from the mesoderm (the middle layer of the trilaminar germ disc) of an embryo. ... Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... Neurons (also called nerve cells) are the primary cells of the nervous system. ... Gametes (in Greek: γαμέτες) —also known as sex cells, germ cells, or spores—are the specialized cells that come together during fertilization (conception) in organisms that reproduce sexually. ... Schematic diagram of a sperm cell, showing the (1) acrosome, (2) cell membrane, (3) nucleus, (4) mitochondria, and (5) flagellum (tail) A sperm cell, or spermatozoon ( spermatozoa) (in Greek: sperm = semen and zoon = alive), is the haploid cell that is the male gamete. ... An oocyte or ovocyte is a female gametocyte that divides twice by mitosis and meiosis into two other oocytes or into two ootids. ... The placenta is an ephemeral (temporary) organ present only in female placental mammals during gestation (pregnancy). ... Mouse embryonic stem cells. ...

Related sciences

Cytology (also known as Cell biology) is the scientific study of cells. ... The pap smear as we know it is an invention of Dr. Georgios Papanikolaou (1883-1962), an American of Greek birth, the father of cytopathology. ... Cell biology (also called cellular biology or cytology, from the Greek kytos, container) is an academic discipline which studies cells. ... Schematic of typical animal cell, showing subcellular components. ... A transmission electron microscope. ... Biochemistry the chemistry of life, a bridge between biology and chemistry that studies how complex chemical reactions give rise to life. ... Anatomical drawing of the human muscles from the Encyclopédie. ... In biology, an organ (Latin: organum, instrument, tool) is a group of tissues, which perform a specific function or group of functions. ... Comparative anatomy is the study of similarities and differences in organisms. ...

Histological artifacts

A histological artifact is a structure or feature that is absent in living tissues, but introduced during preparation or staining. Troubleshooting and minimizing artifacts is a major part of the discipline of histochemistry.


1. Merck Source (2002). Dorland's Medical Dictionary. Retrieved 2005-01-26.

2. Stedman's Medical Dictionaries (2005). Stedman's Online Medical Dictionary. Retrieved 2005-01-26.

See also

Staining is a biochemical technique of adding a class-specific (DNA, proteins, lipids, carbohydrates) dye to a substrate to qualify or quantify the presence of a specific compound. ... // Aerobiology Blackley, C. H. (1873) Experimental Researches on the Causes and Nature of Catarrhus Aestivus (Hay-Fever or Hay-Asthma), (Oxford Historical Books). ... Ubiquitin is a small protein that occurs in all eukaryotic cells. ...

External links

  Results from FactBites:
Article - Histologic features of placentas and abortion specimens from women with antiphospholipid and ... (437 words)
Twenty histologic parameters were systematically assessed by a single investigator who was blinded to the clinical status of the specimens.
There were no histologic differences in tissues from live births and pregnancy losses, or in treated and untreated pregnancies.
Histologic findings in women with APS are non-specific and may not differentiate between women with APS and APS-like syndromes.
  More results at FactBites »



Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m