Editing Lung (section)

=== Function testing ===
{{Main|Pulmonary function testing|Lung volumes}}
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| caption1          = [[Lung volumes]] as described in the text
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| caption2          = A person doing a [[spirometry]] test
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[[Pulmonary function testing|Lung function testing]] is carried out by evaluating a person's capacity to inhale and exhale in different circumstances.<ref name="Ganong2012_34">{{cite book|last1=Kim E.|first1=Barrett|title=Ganong's review of medical physiology|date=2012|publisher=McGraw-Hill Medical|location=New York|isbn=978-0-07-178003-2|chapter=Chapter 34. Introduction to Pulmonary Structure and Mechanics|edition=24th}}</ref> The volume of air inhaled and exhaled by a person at rest is the [[tidal volume]] (normally 500–750&nbsp;mL); the [[inspiratory reserve volume]] and [[expiratory reserve volume]] are the additional amounts a person is able to forcibly inhale and exhale respectively. The summed total of forced inspiration and expiration is a person's [[vital capacity]]. Not all air is expelled from the lungs even after a forced breath out; the remainder of the air is called the [[Lung volumes|residual volume]]. Together these terms are referred to as [[lung volumes]].<ref name="Ganong2012_34" />

Pulmonary [[plethysmograph]]s are used to measure [[functional residual capacity]].<ref>{{cite journal|last1=Criée|first1=C.P.|last2=Sorichter|first2=S.|last3=Smith|first3=H.J.|last4=Kardos|first4=P.|last5=Merget|first5=R.|last6=Heise|first6=D.|last7=Berdel|first7=D.|last8=Köhler|first8=D.|last9=Magnussen|first9=H.|last10=Marek|first10=W.|last11=Mitfessel|first11=H.|last12=Rasche|first12=K.|last13=Rolke|first13=M.|last14=Worth|first14=H.|last15=Jörres|first15=R.A.|title=Body plethysmography – Its principles and clinical use|journal=Respiratory Medicine|date=July 2011|volume=105|issue=7|pages=959–971|doi=10.1016/j.rmed.2011.02.006|pmid=21356587|doi-access=free}}</ref> Functional residual capacity cannot be measured by tests that rely on breathing out, as a person is only able to breathe a maximum of 80% of their total functional capacity.<ref name=Applegate2014 /> The total lung capacity depends on the person's age, height, weight, and sex, and normally ranges between four and six litres.<ref name=Ganong2012_34 /> Females tend to have a 20–25% lower capacity than males. Tall people tend to have a larger total lung capacity than shorter people. [[tobacco smoking|Smokers]] have a lower capacity than nonsmokers. Thinner persons tend to have a larger capacity. Lung capacity can be increased by physical training as much as 40% but the effect may be modified by exposure to air pollution.<ref name=Applegate2014>{{cite book|last1=Applegate|first1=Edith|title=The Anatomy and Physiology Learning System|date=2014|publisher=Elsevier Health Sciences|isbn=978-0-323-29082-1|page=335|url=https://books.google.com/books?id=c8nsAwAAQBAJ&q=factors+that+influence+total+lung+capacity&pg=PA335}}</ref><ref name="Laeremans et al. 2018">{{cite journal  | last = Laeremans  | first = M  | title = Black Carbon Reduces the Beneficial Effect of Physical Activity on Lung Function  | journal = Medicine and Science in Sports and Exercise  | volume =   50| issue = 9  | pages = 1875–1881  | year = 2018  | doi = 10.1249/MSS.0000000000001632| pmid = 29634643  | hdl = 10044/1/63478 | s2cid = 207183760 | hdl-access = free  }}</ref>

Other lung function tests include [[spirometry]], measuring the amount (volume) and flow of air that can be inhaled and exhaled. The maximum volume of breath that can be exhaled is called the [[vital capacity]]. In particular, how much a person is able to exhale in one second (called [[Spirometry#Parameters|forced expiratory volume]] (FEV1)) as a proportion of how much they are able to exhale in total (FEV). This ratio, the FEV1/FEV ratio, is important to distinguish whether a lung disease is [[restrictive lung disease|restrictive]] or [[obstructive lung disease|obstructive]].<ref name=DAVIDSONS2014 /><ref name=Ganong2012_34 /> Another test is that of the lung's  [[diffusing capacity]] – this is a measure of the transfer of gas from air to the blood in the lung capillaries.