Ventilation (physiology): Difference between revisions
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One of the primary roles of the lungs is to facilitate gas exchange between the circulatory system and the external environment. The lungs are constitute of branching airways that terminate in respiratory bronchioles and alveoli, which participate in gas exchange. Most bronchioles and large airways are part of the conducting zone of the lung, which delivers gas to sites of gas exchange in alveoli. Gas exchange occurs in the lungs between alveolar air and the blood of the pulmonary capillaries. For effective gas exchange to occur, alveoli must be ventilated and perfused. Ventilation (V) refers to the flow of air into and out of the alveoli, while perfusion (Q) refers to the flow of blood to alveolar capillaries. Individual alveoli have variable degrees of ventilation and perfusion in different regions of the lungs. Collective changes in ventilation and perfusion in the lungs are measured clinically using the ratio of ventilation to perfusion (V/Q). Changes in the V/Q ratio can affect gas exchange and can contribute to hypoxemia [1]. | |||
In [[respiratory physiology]], '''ventilation''' (or '''ventilation rate''') is the rate at which gas enters or leaves the [[lung]]. It is categorised under the following definitions: | In [[respiratory physiology]], '''ventilation''' (or '''ventilation rate''') is the rate at which gas enters or leaves the [[lung]]. It is categorised under the following definitions: | ||
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==References== | ==References== | ||
<references/> | 1- Wagner PD, Laravuso RB, Uhl RR, West JB. Continuous distributions of ventilation-perfusion ratios in normal subjects breathing air and 100 per cent O2. J Clin Invest. 1974 Jul;54(1):54-68. [PMC free article] [PubMed]<references/> | ||
==External links== | ==External links== | ||
Revision as of 08:00, 18 July 2023
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Christine Henen, MD
One of the primary roles of the lungs is to facilitate gas exchange between the circulatory system and the external environment. The lungs are constitute of branching airways that terminate in respiratory bronchioles and alveoli, which participate in gas exchange. Most bronchioles and large airways are part of the conducting zone of the lung, which delivers gas to sites of gas exchange in alveoli. Gas exchange occurs in the lungs between alveolar air and the blood of the pulmonary capillaries. For effective gas exchange to occur, alveoli must be ventilated and perfused. Ventilation (V) refers to the flow of air into and out of the alveoli, while perfusion (Q) refers to the flow of blood to alveolar capillaries. Individual alveoli have variable degrees of ventilation and perfusion in different regions of the lungs. Collective changes in ventilation and perfusion in the lungs are measured clinically using the ratio of ventilation to perfusion (V/Q). Changes in the V/Q ratio can affect gas exchange and can contribute to hypoxemia [1].
In respiratory physiology, ventilation (or ventilation rate) is the rate at which gas enters or leaves the lung. It is categorised under the following definitions:
| Measurement | Equation | Description |
| Minute ventilation | = tidal volume * respiratory rate[1][2] | the total volume of gas entering the lungs per minute. |
| Alveolar ventilation | = (tidal volume - dead space) * respiratory rate [1] | the volume of gas per unit time that reaches the alveoli, the respiratory portions of the lungs where gas exchange occurs. |
| Dead space ventilation | = dead space * respiratory rate[3] | is the volume of gas per unit time that does not reach these respiratory portions, but instead remains in the airways (trachea, bronchi, etc.). |
See also
References
1- Wagner PD, Laravuso RB, Uhl RR, West JB. Continuous distributions of ventilation-perfusion ratios in normal subjects breathing air and 100 per cent O2. J Clin Invest. 1974 Jul;54(1):54-68. [PMC free article] [PubMed]
- ↑ 1.0 1.1 http://www.healthsystem.virginia.edu/Internet/Anesthesiology-Elective/airway/ventilation.cfm
- ↑ http://www.nda.ox.ac.uk/wfsa/html/u12/u1211_02.htm
- ↑ Essentials of Human Physiology by Thomas M. Nosek. Section 4/4ch3/s4ch3_16.
External links
- Pulmonary+ventilation at the US National Library of Medicine Medical Subject Headings (MeSH)