Célula de Clara: Diferenzas entre revisións
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==Funcións== |
==Funcións== |
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A principal función das células de Clara é protexer o epitelio dos bronquiolos. Fano segregando diversos produtos, como a [[proteína secretora da célula de Clara]] (CCSP) e unha solución similar á do compoñente do [[surfactante]] pulmonar. Crese que tamén son responsables de detoxificar substancias nocivas inhaladas, que chegan aos bronquiolos. As células de Clara realizan isto utilizando os encimas [[citocromo P450]] do seu [[retículo endoplasmático]] liso. Ademais, actúan como [[célula nai|células nais]], que se multiplican e diferencian en células ciliadas que rexeneran o epitelio bronquiolar. <ref>http://medical-dictionary.thefreedictionary.com/Clara+cell</ref> |
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==Mecanismo== |
==Mecanismo== |
Revisión como estaba o 22 de xaneiro de 2012 ás 18:01
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Clara cells are dome-shaped cells with short microvilli found in the small airways (bronchioles) of the lungs.[1] Clara cells are found in the ciliated simple epithelium. These cells may secrete glycosaminoglycans to protect the bronchiole lining.Bronchiolar cells gradually increase in number as the number of goblet cells decrease.
They are also known as "bronchiolar exocrine cells".[2]
Historia e nome
As células de Clara reciben ese nome polo seu descubridor Max Clara, que as describiu en 1937. Max Clara (1899-1966) naceu no Tirol e foi un médico nazi, que utilizou nas súas investigacións e na descrición das células de Clara tecidos procedentes de vítimas executadas polo Terceiro Reich. [3] [4]
Funcións
A principal función das células de Clara é protexer o epitelio dos bronquiolos. Fano segregando diversos produtos, como a proteína secretora da célula de Clara (CCSP) e unha solución similar á do compoñente do surfactante pulmonar. Crese que tamén son responsables de detoxificar substancias nocivas inhaladas, que chegan aos bronquiolos. As células de Clara realizan isto utilizando os encimas citocromo P450 do seu retículo endoplasmático liso. Ademais, actúan como células nais, que se multiplican e diferencian en células ciliadas que rexeneran o epitelio bronquiolar. [5]
Mecanismo
The respiratory bronchioles represent the transition from the conducting portion to the respiratory portion of the respiratory system. The narrow channels are usually less than 2 mm in diameter and they are lined by a simple cuboidal epithelium, consisting of ciliated cells and non-ciliated Clara cells, which are unique to bronchioles. In addition to being structurally diverse, Clara cells are also functionally variable. One major function they carry out is the synthesis and secretion of the material lining the bronchiolar lumen. This material includes glycosaminoglycans, proteins such as lysozymes, and conjugation of the secretory portion of IgA antibodies. These play an important defensive role, and they also contribute to the degradation of the mucus produced by the upper airways. The heterogeneous nature of the dense granules within the Clara cell's cytoplasm suggests that they may not all have a secretory function. Some of them may contain lysosomal enzymes, which carry out a digestive role, either in defense: Clara cells engulf airborne toxins and break them down via their cytochrome P-450 enzymes (particularly CYP4B1, which is only present in the clara cells) present in their smooth endoplasmic reticulum; or in the recycling of secretory products. Clara cells are mitotically active cells. They divide and differentiate to form both ciliated and non-ciliated epithelial cells.
Enfermidades
Clara cells contain Tryptase clara, which is believed to be responsible for cleaving the hemagglutinin surface protein of influenza A virus, thereby activating it and causing the symptoms of flu.[6] When the l7Rn6 protein is disrupted in mice, these mice display severe emphysema at birth as a result of disorganization of the Golgi apparatus and formation of aberrant vesicular structures within clara cells.[7]
Notas
- ↑ Atkinson JJ, Adair-Kirk TL, Kelley DG, Demello D, Senior RM (2008). "Clara cell adhesion and migration to extracellular matrix". Respir. Res. 9 (1): 1. PMC 2249579. PMID 18179694. doi:10.1186/1465-9921-9-1.
- ↑ Peter J. Papadakos; Burkhard Lachmann (29 August 2007). Mechanical Ventilation: Clinical Applications and Pathophysiology. Elsevier Health Sciences. pp. 74–. ISBN 9780721601861. Consultado o 27 May 2011.
- ↑ Winkelmann, Andreas; Noack, Thorsten (2010). "The Clara cell - a "Third Reich eponym"?". European Respiratory Journal Express 36 (4): 722–7. PMID 20223917. doi:10.1183/09031936.00146609.
- ↑ Pringle, Heather (2010). "The Dilemma of Pernkopf's Atlas". Science 329 (5989): 274–275. PMID 20647444. doi:10.1126/science.329.5989.274-b.
- ↑ http://medical-dictionary.thefreedictionary.com/Clara+cell
- ↑ Taubenberger JK (1998). "Influenza virus hemagglutinin cleavage into HA1, HA2: No laughing matter". Proc. Natl. Acad. Sci. U.S.A. 95 (17): 9713–5. PMC 33880. PMID 9707539. doi:10.1073/pnas.95.17.9713. Parámetro descoñecido
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ignorado (Axuda) - ↑ Fernández-Valdivia R, Zhang Y, Pai S, Metzker ML, Schumacher A (2006). "l7Rn6 Encodes a Novel Protein Required for Clara Cell Function in Mouse Lung Development". Genetics 172 (1): 389–99. PMC 1456166. PMID 16157679. doi:10.1534/genetics.105.048736. Parámetro descoñecido
|month=
ignorado (Axuda)
Véxase tamén
Outros artigos
Ligazóns externas
- Imaxe de Histoloxía: 13805loa – Histology Learning System na Universidade de Boston
- Modelo:GPnotebook
- UIUC Histology Subject 1385
- Histology at ucsf.edu