atrophy

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For more information on atrophy, visit Britannica.com.

Autopsy results showed that Terri Schiavo, who died in March 2005 after her feeding tube was disconnected, had massive and irreversible brain damage, contrary to the claims of her parents, who said she was capable of improvement:

"An autopsy... found that her brain had atrophied to less than half the normal size, medical examiner Jon Thogmartin said."

Link: Schiavo autopsy: There was no hope

Posted June 16, 2005.

See our Word Overheard blog to see interesting uses of strange words.

Wasting of normally developed tissue or muscle as a result of disuse, ageing, or under-nutrition.

A reduction in the size or wasting away of an organ or tissue from lack of use or disease. Inactivity results in weakening of both muscles and bones. Space scientists with NASA found that complete immobilization for three days resulted in astronauts losing one-fifth of maximal strength. Early space flights at zero gravity resulted in leg bones becoming thinner and susceptible to fractures. The scientists found that weight-bearing exercises reversed the degenerative changes. They recommended daily exercise, but suggested that three non-consecutive days of programmed activity was sufficient to maintain physical fitness.

The effects of a sedentary lifestyle are not as dramatic as immobilization in space, but the space research supports the notion that ‘if you don't use it, you'll lose it’. See also hypokinetic disease.

The word comes from the Greek, meaning ‘ill-fed’. In biomedical terms it means wasting — loss of mass from a tissue or organ from whatever cause. It is used as a verb: muscles, for example, can atrophy with simple disuse; or as a noun (they undergo disuse atrophy) ; or, they become atrophied if their nerves are damaged, so that they can no longer be stimulated into action. Another type — closer to ‘ill-feeding’ — is ischaemic atrophy from deprivation of blood supply, such as may happen in parts of the brain after stroke or severe head injury, or in heart muscle in coronary artery disease. Atrophy also happens in the normal course of events to cells or tissues which have fulfilled their useful life (such as umbilical blood vessels after birth or ovaries after the menopause) or as cells die off progressively with age (as in kidneys and brain).

— Sheila Jennett

See also dementia; muscle wasting.

noun

Descent to a lower level or condition: decadence, declension, declination, decline, degeneracy, degeneration, deterioration. See better/worse.

verb

To become lower in quality, character, or condition: decline, degenerate, descend, deteriorate, retrograde, sink, worsen. Idioms: go bad, go to pot, go to seed, go to the dogs. See better/worse.

Definition: wasting
Antonyms: strengthening

v

Definition: peter out
Antonyms: flourish

v

Definition: waste away
Antonyms: strengthen

Reduction in size or wasting away of an organ or tissue from lack of use or disease. Atrophy begins very quickly if training is stopped or if a muscle is immobilized. During the first week of muscle immobilization, strength decreases averaging 3-4% each day are associated with muscle atrophy. Muscle atrophy can be avoided if training is reduced, as in a maintenance programme, rather than stopped.

The wasting away or decrease in size of an organ or tissue in the body. When a body part is affected by paralysis, the muscles may atrophy through lack of use.

Characterized by atrophy.

• a. dermatosis — characterized by epithelial and connective tissue atrophy; a common accompaniment of endocrine disorders and nutritional deficiencies.
• ovarian a. cyst — anovulatory cystic follicles causing failure of estrus in most cases; a common cause of infertility in cows.
• a. rhinitis — a disease primarily of young pigs causing deformities of the facial and turbinate bones which persist for life. Clinically there is an initial attack of acute rhinitis manifested by sneezing and snout rubbing, followed by crumpling of the face often with a distortion to one side.

A progressive, acquired decrease in the size of a normally developed cell, tissue, or organ. Atrophy may result from a decrease in cell size, number of cells, or both.

• Inert, Lazy, Tired, or Insensate

For the American thrash metal band, see Atrophy (band)

Atrophy
Classification and external resources
Mice with spinal muscular atrophy
MeSH	D001284

Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, excessive amount of apoptosis of cells, and disuse or lack of exercise or disease intrinsic to the tissue itself. Hormonal and nerve inputs that maintain an organ or body part are referred to as trophic [noun] in medical practice ('trophic" is an adjective that can be paired with various nouns). Trophic describes the trophic condition of tissue. A diminished muscular trophic is designated as atrophy.

Atrophy is the general physiological process of reabsorption and breakdown of tissues, involving apoptosis on a cellular level. When it occurs as a result of disease or loss of trophic support due to other disease, it is termed pathological atrophy, although it can be a part of normal body development and homeostasis as well.

Contents 1 Atrophy examples 1.1 Normal development 1.2 Muscle atrophies 1.3 Dystrophies, myosities, and motor neuron conditions 1.4 Gland atrophy 1.5 Vaginal atrophy 1.6 Respiration 2 Research 3 See also 4 References

Atrophy examples

Normal development

Examples of atrophy as part of normal development include shrinking and the involution of the thymus in early childhood, and the tonsils in adolescence.

Muscle atrophies

Main article: Muscle atrophy

Disuse atrophy of muscles (muscle atrophy) and bones, with loss of mass and strength, can occur after prolonged immobility, such as extended bedrest, or having a body part in a cast (living in darkness for the eye, bedridden for the legs etc.). This type of atrophy can usually be reversed with exercise unless severe. Astronauts in microgravity must exercise regularly to minimize atrophy of their limb muscles.

There are many diseases and conditions which cause atrophy of muscle mass. For example diseases such as cancer and AIDS induce a body wasting syndrome called "cachexia", which is notable for the severe muscle atrophy seen. Other syndromes or conditions which can induce skeletal muscle atrophy are congestive heart failure and liver disease.

During aging, there is a gradual decrease in the ability to maintain skeletal muscle function and mass. This condition is called "sarcopenia", and may be distinct from atrophy in its pathophysiology. While the exact cause of sarcopenia is unknown, it may be induced by a combination of a gradual failure in the "satellite cells" which help to regenerate skeletal muscle fibers, and a decrease in sensitivity to or the availability of critical secreted growth factors which are necessary to maintain muscle mass and satellite cell survival.^[1]

Dystrophies, myosities, and motor neuron conditions

Pathologic atrophy of muscles can occur with diseases of the motor nerves, or diseases of the muscle tissue itself. Examples of atrophying nerve diseases include CMT (Charcot Marie Tooth syndrome) poliomyelitis, amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), and Guillain-Barré syndrome. Examples of atrophying muscle diseases include muscular dystrophy, myotonia congenita, and myotonic dystrophy.

Changes in Na+ channel isoform expression and spontaneous activity in muscle called fibrillation can also result in muscle atrophy.

Gland atrophy

The adrenal glands atrophy during prolonged use of exogenous glucocorticoids like prednisone. Atrophy of the breasts can occur with prolonged estrogen reduction, as with anorexia nervosa or menopause. Atrophy of the testes occurs with prolonged use of enough exogenous sex steroid (either androgen or estrogen) to reduce gonadotropin secretion.

Vaginal atrophy

In post-menopausal women, the walls of the vagina become thinner (Atrophic vaginitis). The mechanism for the age-related condition is not yet clear, though there are theories that the effect is caused by decreases in estrogen levels.^[2] This atrophy, and that of the breasts concurrently, is consistent with the homeostatic (normal development) role of atrophy in general, as after menopause the body has no further functional biological need to maintain the reproductive system which it has permanently shut down.

Respiration

In most amphibians and the South-American and African lungfishes, the animals stop breathing through gills and start using lungs instead as they develop towards adult forms.

Research

It has been reported that some drugs might prevent the loss of the muscle wasting that occurs in immobile, bedridden patients.^[3] Testing upon mice showed that it blocked the activity of a protein present in the muscle that is involved in muscle atrophy.^[4] However the concerns for the drug's long-term effects on the heart preclude its routine use in humans for this indication, and further alternative drugs are being sought.^[3] Not exercising is the main cause for muscle atrophy.

See also

• Olivopontocerebellar atrophy
• Optic atrophy
• Spinomuscular atrophy
• Testicular atrophy
• Hypertrophy

References

1. ^ Campellone, Joseph V. (2007-05-22). "Muscle atrophy" (html). MedlinePlus. http://www.nlm.nih.gov/medlineplus/ency/article/003188.htm. Retrieved 2007-10-02. 
2. ^ "Types of Atrophy" (html). http://medicine.science-tips.org/health/diseases-and-conditions/types-of-atrophy.html. Retrieved 2007-10-02. 
3. ^ ^{a b} "Drug could stop muscle wasting'". NetDoctor.co.uk. 2006-05-25. http://www2.netdoctor.co.uk/news/index.asp?y=2006&m=5&d=25&id=123026. Retrieved 2006-05-27. ^{[dead link]}
4. ^ Wang X, Hockerman GH, Green Iii HW, Babbs CF, Mohammad SI, Gerrard D, Latour MA, London B, Hannon KM, Pond AL (May24 2006). "Merg1a K+ channel induces skeletal muscle atrophy by activating the ubiquitin proteasome pathway". FASEB J 20 (9): 1531. doi:10.1096/fj.05-5350fje. PMID 16723379. 

v t e Medicine: Pathology Principles of pathology Disease/Medical condition Infection Neoplasia Hemodynamics Ischemia Inflammation Wound healing Cell death Necrosis Liquefactive necrosis Coagulative necrosis Caseous necrosis Fat necrosis Apoptosis Pyknosis Karyorrhexis Karyolysis Cellular adaptation Atrophy Hypertrophy Hyperplasia Dysplasia Metaplasia Squamous Glandular Accumulations: pigment Hemosiderin Lipochrome/Lipofuscin Melanin Steatosis Anatomical pathology Surgical pathology Cytopathology Autopsy Molecular pathology Forensic pathology Dental pathology Gross examination Histopathology Immunohistochemistry Electron microscopy Immunofluorescence Fluorescent in situ hybridization Clinical pathology Clinical chemistry Hematopathology Transfusion medicine Medical microbiology Diagnostic immunology Immunopathology Enzyme assay Mass spectrometry Chromatography Flow cytometry Blood bank Microbiological culture Serology Specific conditions Myocardial infarction

v t e Clinical and histological nomenclature for skin lesions Macroscopic Primary lesions flat (Macule, Patch) · elevated (Papule, Nodule, Plaque) · fluid (Vesicle, Bulla, Pustule) · Ulcer · Erosion · Telangiectasia Special initial lesions : Burrow (Tunnel)  · Comedone · Scutulum · Target lesion · Herald patch  · Wheal Secondary lesions Scale · Crust · Lichenification · Excoriation · Induration · Atrophy Microscopic keratin: Hyperkeratosis · Parakeratosis · Dyskeratosis Hypergranulosis · Acanthosis · Papillomatosis · Acantholysis · Spongiosis · Hydropic swelling · Exocytosis · Vacuolization · Erosion · Ulceration · Lentiginous

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Dansk (Danish)
v. tr. - forårsage atropi, få til at svinde
v. intr. - svinde, tæres
n. - atrofi, henfald, svind

Nederlands (Dutch)
(doen) wegkwijnen, wegkwijning, verval

Français (French)
v. tr. - atrophier
v. intr. - s'atrophier
n. - atrophie

Deutsch (German)
v. - (med.) atrophieren, verkümmern
n. - (med.) Atrophie, Verkümmerung

Ελληνική (Greek)
v. - ατροφώ, μαραίνομαι, επιφέρω ατροφία
n. - ατροφία, απίσχνανση, καχεξία

Italiano (Italian)
atrofizzare, atrofia

Português (Portuguese)
v. - atrofiar, arruinar, retardar
n. - atrofia (f) (Med.) (Zool.) (Anat.)

Русский (Russian)
атрофироваться, атрофия

Español (Spanish)
v. tr. - atrofiar
v. intr. - atrofiarse, padecer una atrofia
n. - atrofia

Svenska (Swedish)
v. - förtvina, trubbas av
n. - förtvining, avtrubbning

中文（简体）(Chinese (Simplified))
萎缩, 虚脱, 衰退, 发育停止, 减缩

中文（繁體）(Chinese (Traditional))
v. tr. - 萎縮, 虛脫
v. intr. - 萎縮, 衰退
n. - 萎縮, 虛脫, 發育停止, 減縮

한국어 (Korean)
v. tr. - 위축시키다
v. intr. - 위축하다
n. - 위축[증], 쇠퇴

日本語 (Japanese)
n. - 萎縮, 衰退
v. - 萎縮させる, やせ衰えさせる

العربيه (Arabic)
‏(فعل) يضمر, توقف عن النمو من قله التغذيه أو الإستعمال (الاسم) ضمور, توقف النمو‏

עברית (Hebrew)
v. tr. - ‮ניוון‬
v. intr. - ‮התנוון‬
n. - ‮התנוונות, הידלדלות, התכלות‬

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