Editing Lung (section)

====Connective tissue====
[[File:STD 190219 SWITCH Tissue 2 93x CMLE 20SNR 50IT Elastin.png|thumb|Thick [[elastic fibres]] from the [[visceral pleura]] (outer lining) of lung]]
[[File:Fibers of Collagen Type I - TEM.jpg|thumb|[[Transmission electron microscopy|TEM]] image of [[collagen fibres]] in a cross sectional slice of mammalian lung tissue]]
The connective tissue of the lungs is made up of [[Elastic fiber|elastic]] and [[collagen fibres ]] that are interspersed between the capillaries and the alveolar walls. [[Elastin]] is the key [[protein]] of the [[extracellular matrix]] and is the main component of the [[elastic fibres]].<ref name="Mithieux">{{cite book |doi=10.1016/S0065-3233(05)70013-9 |chapter=Elastin |title=Fibrous Proteins: Coiled-Coils, Collagen and Elastomers |series=Advances in Protein Chemistry |year=2005 |last1=Mithieux |first1=Suzanne M. |last2=Weiss |first2=Anthony S. |volume=70 |pages=437–461 |pmid=15837523 |isbn=9780120342709 }}</ref> Elastin gives the necessary elasticity and resilience required for the persistent stretching involved in breathing, known as [[lung compliance]]. It is also responsible for the [[elastic recoil]] needed. Elastin is more concentrated in areas of high stress such as the openings of the alveoli, and alveolar junctions.<ref name="Mithieux"/> The connective tissue links all the alveoli to form the lung parenchyma which has a sponge-like appearance. The alveoli have interconnecting air passages in their walls known as the [[pores of Kohn]].<ref name=Pocock/>