Editing Asthma (section)

==Pathophysiology==
{{Main|Pathophysiology of asthma}}
{{multiple image
| total_width       = 660
| image1            = Asthma attack-illustration NIH.jpg
| caption1          = Figure A shows the location of the lungs and airways in the body. Figure B shows a cross-section of a normal airway. Figure C shows a cross-section of an airway during asthma symptoms.
| image2            = Asthma .jpg
| alt2              = A tissue cross section of the airway showing a stained pink wall and an inside full of white mucous
| caption2          = Obstruction of the lumen of a [[bronchiole]] by mucoid exudate, [[goblet cell metaplasia]], and epithelial [[basement membrane]] thickening in a person with asthma
| image3            = Asthma (Lungs).png
| caption3          = Diagram of asthma
}}
Asthma is the result of chronic [[inflammation]] of the [[conducting zone]] of the airways (most especially the [[bronchus|bronchi]] and [[bronchiole]]s), which subsequently results in increased contractability of the surrounding [[smooth muscle]]s.<ref name=GINA2011p2/> This among other factors leads to bouts of narrowing of the airway and the classic symptoms of wheezing. The narrowing is typically reversible with or without treatment. Occasionally the airways themselves change.<ref name=GINA2011p2/> Typical changes in the airways include an increase in [[eosinophils]] and thickening of the [[lamina reticularis]].<ref name=M38/> Chronically, the airways' smooth muscle may increase in size along with an increase in the numbers of mucous glands.<ref name=M38/> Other cell types involved include [[T lymphocytes]], [[macrophages]], and [[neutrophils]]. There may also be involvement of other components of the [[immune system]], including [[cytokines]], [[chemokines]], [[histamine]], and [[leukotrienes]] among others.<ref name=M38/>