# Atrophy > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Atrophy > Markdown URL: https://mediated.wiki/source/Atrophy.md > Source: https://en.wikipedia.org/wiki/Atrophy > Source revision: 1323544297 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Not to be confused with [Entropy](/source/Entropy). For the American thrash metal band, see [Atrophy (band)](/source/Atrophy_(band)). Partial or complete wasting away of a part of the body Medical condition Atrophy Mouse (right) with spinal muscular atrophy Specialty Pathology Symptoms Loss of body cells, signs of ageing Types Muscular atrophy, gland atrophy Causes Poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to target organ(s), excessive apoptosis of cells, insufficient exercise, ageing Risk factors Old age, sedentary lifestyle Prognosis Depends on the cause **Atrophy** is the partial or complete [wasting](/source/Wasting) away of a part of the body. Causes of atrophy include [mutations](/source/Mutation) (which can destroy the gene to build up the organ), [poor nourishment](/source/Malnutrition), poor [circulation](/source/Circulatory_system), loss of [hormonal](/source/Hormone) support, loss of [nerve](/source/Nerve) supply to the target [organ](/source/Organ_(biology)), excessive amount of [apoptosis](/source/Apoptosis) of cells, and disuse or lack of [exercise](/source/Exercise) or disease intrinsic to the tissue itself. In medical practice, hormonal and nerve inputs that maintain an organ or body part are said to have *trophic* effects. A diminished muscular trophic condition is designated as *atrophy*. Atrophy is reduction in size of cell, organ or tissue, after attaining its normal mature growth. In contrast, [hypoplasia](/source/Hypoplasia) is the reduction in the cellular numbers of an organ, or tissue that has not attained normal maturity. Atrophy is the general [physiological](/source/Physiology) process of reabsorption and breakdown of [tissues](/source/Tissue_(biology)), involving apoptosis. When it occurs as a result of disease or loss of trophic support because of other diseases, it is termed *pathological atrophy*, although it can be a part of normal body development and [homeostasis](/source/Homeostasis) as well. ## Normal development -plasia and -trophy Anaplasia (structural differentiation loss within a cell or group of cells). Aplasia (organ or part of organ missing) Desmoplasia (connective tissue growth) Dysplasia (change in cell or tissue phenotype) Hyperplasia (proliferation of cells) Hypoplasia (congenital below-average number of cells, especially when inadequate) Metaplasia (conversion in cell type) Neoplasia (abnormal proliferation) Prosoplasia (development of new cell function) Abiotrophy (loss in vitality of organ or tissue) Atrophy (reduced functionality of an organ, with decrease in the number or volume of cells) Hypertrophy (increase in the volume of cells or tissues) Hypotrophy (decrease in the volume of cells or tissues) Dystrophy (any degenerative disorder resulting from improper or faulty nutrition) v t e Examples of atrophy as part of normal development include shrinking and the involution of the [thymus](/source/Thymus) in early childhood, and the [tonsils](/source/Tonsil) in adolescence. In old age, effects include, but are not limited to, loss of teeth, hair, thinning of skin that creates wrinkles, weakening of muscles, loss of weight in organs and sluggish mental activity.[1] ## Muscle atrophies Main article: [Muscle atrophy](/source/Muscle_atrophy) *Disuse atrophy* of muscles and bones, with loss of mass and strength, can occur after prolonged immobility, such as extended [bedrest](/source/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. 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](/source/Cachexia)*, which is notable for the severe muscle atrophy seen. Other syndromes or conditions which can induce [skeletal muscle](/source/Skeletal_muscle) atrophy are [congestive heart failure](/source/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](/source/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](/source/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.[2] ## Dystrophies, myositis, 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 [Charcot-Marie-Tooth disease](/source/Charcot-Marie-Tooth_disease), [poliomyelitis](/source/Poliomyelitis), [amyotrophic lateral sclerosis](/source/Amyotrophic_lateral_sclerosis) (ALS or Lou Gehrig's disease), and [Guillain–Barré syndrome](/source/Guillain%E2%80%93Barr%C3%A9_syndrome). Examples of atrophying muscle diseases include [muscular dystrophy](/source/Muscular_dystrophy), [myotonia congenita](/source/Myotonia_congenita), and [myotonic dystrophy](/source/Myotonic_dystrophy). Changes in Na+ channel isoform expression and spontaneous activity in muscle called fibrillation can also result in muscle atrophy. A [flail limb](/source/Flail_limb) is a medical term which refers to an extremity in which the primary nerve has been severed, resulting in complete lack of mobility and sensation. The muscles soon wither away from atrophy. ## Gland atrophy The [adrenal glands](/source/Adrenal_gland) atrophy during prolonged use of exogenous [glucocorticoids](/source/Glucocorticoid) like [prednisone](/source/Prednisone). Atrophy of the breasts can occur with prolonged [estrogen](/source/Estrogen) reduction, as with [anorexia nervosa](/source/Anorexia_nervosa) or [menopause](/source/Menopause). [Testicular atrophy](/source/Testicular_atrophy) can occur with prolonged use of enough exogenous [sex steroids](/source/Sex_steroid) (either [androgen](/source/Androgen) or [estrogen](/source/Estrogen)) to reduce [gonadotropin](/source/Gonadotropin) secretion. ## Vaginal atrophy In post-menopausal women, the walls of the vagina become thinner ([atrophic vaginitis](/source/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.[3] This atrophy, occurring concurrently with [breast atrophy](/source/Breast_atrophy), 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. ## Research One drug in test seemed to prevent the type of muscle loss that occurs in immobile, bedridden patients.[4] Testing on mice showed that it blocked the activity of a protein present in the muscle that is involved in muscle atrophy.[5] However, the drug's long-term effect on the heart precludes its routine use in humans, and other drugs are being sought.[4] ## See also - [Olivopontocerebellar atrophy](/source/Olivopontocerebellar_atrophy) - [Optic atrophy](/source/Optic_atrophy) - [Spinomuscular atrophy](/source/Spinomuscular_atrophy) - [Hypertrophy](/source/Hypertrophy) - [Deconditioning](/source/Deconditioning) - [List of biological development disorders](/source/List_of_biological_development_disorders) ## References 1. **[^](#cite_ref-1)** W. T. Councilman (1913). "Chapter Two". [*Disease and Its Causes*](https://www.gutenberg.org/files/15283/15283-h/15283-h.htm#toc_5). New York Henry Holt and Company London [Williams and Norgate](/source/Williams_and_Norgate) The University Press, Cambridge, U.S. 1. **[^](#cite_ref-2)** Campellone, Joseph V. (2007-05-22). ["Muscle atrophy"](https://www.medlineplus.gov/ency/article/003188.htm). [MedlinePlus](/source/MedlinePlus). [Archived](https://web.archive.org/web/20071013000952/http://www.nlm.nih.gov/medlineplus/ency/article/003188.htm) from the original on 13 October 2007. Retrieved 2007-10-02. 1. **[^](#cite_ref-3)** ["Types of Atrophy"](https://web.archive.org/web/20070928072029/http://medicine.science-tips.org/health/diseases-and-conditions/types-of-atrophy.html). Archived from [the original](http://medicine.science-tips.org/health/diseases-and-conditions/types-of-atrophy.html) on 28 September 2007. Retrieved 2007-10-02. 1. ^ [***a***](#cite_ref-ND2006_4-0) [***b***](#cite_ref-ND2006_4-1) ["Drug could stop muscle wasting'"](https://web.archive.org/web/20070911010834/http://www2.netdoctor.co.uk/news/index.asp?y=2006&m=5&d=25&id=123026). NetDoctor.co.uk. 2006-05-25. Archived from [the original](http://www2.netdoctor.co.uk/news/index.asp?y=2006&m=5&d=25&id=123026) on 2007-09-11. Retrieved 2006-05-27. 1. **[^](#cite_ref-FASEBJ2006-Wang_5-0)** Wang X, Hockerman GH, Green Iii HW, Babbs CF, Mohammad SI, Gerrard D, Latour MA, London B, Hannon KM, Pond AL (May 24, 2006). ["Merg1a K+ channel induces skeletal muscle atrophy by activating the ubiquitin proteasome pathway"](https://doi.org/10.1096%2Ffj.05-5350fje). *FASEB J*. **20** (9): 1531–3. [doi](/source/Doi_(identifier)):[10.1096/fj.05-5350fje](https://doi.org/10.1096%2Ffj.05-5350fje). [PMID](/source/PMID_(identifier)) [16723379](https://pubmed.ncbi.nlm.nih.gov/16723379). [S2CID](/source/S2CID_(identifier)) [15763153](https://api.semanticscholar.org/CorpusID:15763153). ## External links - ["Atrophy"](https://en.wikisource.org/wiki/Encyclop%C3%A6dia_Britannica,_Ninth_Edition/Atrophy). *[Encyclopædia Britannica](/source/Encyclop%C3%A6dia_Britannica)*. Vol. III (9th ed.). 1878. pp. 50–51. Classification D MeSH: D001284 SNOMED CT: 13331008 v t e Pathology History Principles of pathology Disease Infection Neoplasia Cause Pathogenesis Hemodynamics Ischemia Inflammation Cell damage Wound healing Cellular adaptation Atrophy Hypertrophy Hyperplasia Dysplasia Metaplasia Squamous Glandular Cell death Necrosis Coagulative necrosis Liquefactive necrosis Gangrenous necrosis Caseous necrosis Fat necrosis Fibrinoid necrosis Myocytolysis Programmed cell death Apoptosis Pyknosis Karyorrhexis Karyolysis Accumulations pigment Hemosiderin Lipochrome/Lipofuscin Melanin Steatosis Anatomical pathology Surgical pathology Cytopathology Autopsy Molecular pathology Forensic pathology Oral and maxillofacial pathology Gross processing Histopathology Immunohistochemistry Electron microscopy Immunofluorescence Fluorescence 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 Category Commons v t e Skin lesion terminology Macroscopic Primary lesions flat Macule Patch elevated Papule Nodule Plaque fluid Vesicle Bulla Pustule Ulcer Erosion Telangiectasia Special initial lesions : Burrow Tunnel Comedo 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 Authority control databases International GND National United States Israel Other Yale LUX --- Adapted from the Wikipedia article [Atrophy](https://en.wikipedia.org/wiki/Atrophy) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Atrophy?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.