Lung Volumes

the volume of the air contained in the lungs at various degrees of thoracic expansion.

With maximum exhalation, the gaseous contents of the lungs decrease to the residual volume (RV). The normal inhalation position adds to this the expiratory reserve volume (ERV), or the reserve air. The tidal volume (TV) is added by the end of inhalation (respiratory air). The inspiratory reserve volume (IRV), or complemental air, is added by the end of maximum inhalation.

The sum of the RV and the ERV is called the functional residual capacity (FRC); the sum of the TV and the IRV, the inspiratory capacity (IC); the sum of the ERV, the TV, and the IRV, the vital capacity (VC); and the sum of the RV, the ERV, the TV, and the IRV, the total capacity (TC) of the lungs. All lung volumes, with the exception of the RV and the TC, can be determined by measuring the volume of air exhaled into a spirometer or spirograph. The RV, the FRC, and the TC can be measured by inhaling an indicator gas, establishing its degree of diffusion in the lungs by gas analysis.

Lung volumes depend on height (directly), age (inversely, after age 30), sex (10–20 percent less in women than in men), and physical development (20–30 percent greater in athletes). Tables, nomograms, and formulas have been worked out for determining the VC and lung volumes expected in healthy persons (see Figure 1). Lung volumes are expressed as absolute (in ml) and relative (in percentages of the necessary volumes and TC) quantities. In men, the VC is 3,500–4,500 ml (in some cases reaching 6,000 ml); in women, 2,500–3,500 ml. Determination of the lung volumes is important in evaluating the condition of the external respiratory system. The volumes undergo characteristic changes with many diseases (especially diseases of the respiratory and cardiovascular systems).

Figure 1. Lung volumes and capacities in a healthy adult male

L. L. SHIK

lung volumes

Physiology A group of air 'compartments' into which the lung may be functionally divided Lung volumes
Expiratory reserve capacity–ERV The maximum volume of air that can be voluntarily exhaled Functional residual capacity (FRV) Volume left in the lungs at the end of a normal breath which is not normally part of the subdivisions Inspiratory capacity–IC The maximum volume that can be inhaled Inspiratory Reserve capacity–IRC The maximum volume that can be inhaled above the tidal volume Tidal volume–V_T The normal to-and-fro respiratory exchange of 500 cc; vital capacity is the maximum amount of exhalable air; after a full inspiration, which added to the residual volume, is the total lung capacity Total lung capacity–TLC The entire volume of the lung, circa 5 liters Vital capacity–VC The maximum volume that can be inhaled and exhaled

单词	lung volumes
释义	DictionarySeelungs Lung Volumes Lung Volumes the volume of the air contained in the lungs at various degrees of thoracic expansion. With maximum exhalation, the gaseous contents of the lungs decrease to the residual volume (RV). The normal inhalation position adds to this the expiratory reserve volume (ERV), or the reserve air. The tidal volume (TV) is added by the end of inhalation (respiratory air). The inspiratory reserve volume (IRV), or complemental air, is added by the end of maximum inhalation. The sum of the RV and the ERV is called the functional residual capacity (FRC); the sum of the TV and the IRV, the inspiratory capacity (IC); the sum of the ERV, the TV, and the IRV, the vital capacity (VC); and the sum of the RV, the ERV, the TV, and the IRV, the total capacity (TC) of the lungs. All lung volumes, with the exception of the RV and the TC, can be determined by measuring the volume of air exhaled into a spirometer or spirograph. The RV, the FRC, and the TC can be measured by inhaling an indicator gas, establishing its degree of diffusion in the lungs by gas analysis. Lung volumes depend on height (directly), age (inversely, after age 30), sex (10–20 percent less in women than in men), and physical development (20–30 percent greater in athletes). Tables, nomograms, and formulas have been worked out for determining the VC and lung volumes expected in healthy persons (see Figure 1). Lung volumes are expressed as absolute (in ml) and relative (in percentages of the necessary volumes and TC) quantities. In men, the VC is 3,500–4,500 ml (in some cases reaching 6,000 ml); in women, 2,500–3,500 ml. Determination of the lung volumes is important in evaluating the condition of the external respiratory system. The volumes undergo characteristic changes with many diseases (especially diseases of the respiratory and cardiovascular systems). Figure 1. Lung volumes and capacities in a healthy adult male L. L. SHIK lung volumes lung volumes Physiology A group of air 'compartments' into which the lung may be functionally divided Lung volumes Expiratory reserve capacity–ERV The maximum volume of air that can be voluntarily exhaled Functional residual capacity (FRV) Volume left in the lungs at the end of a normal breath which is not normally part of the subdivisions Inspiratory capacity–IC The maximum volume that can be inhaled Inspiratory Reserve capacity–IRC The maximum volume that can be inhaled above the tidal volume Tidal volume–V_T The normal to-and-fro respiratory exchange of 500 cc; vital capacity is the maximum amount of exhalable air; after a full inspiration, which added to the residual volume, is the total lung capacity Total lung capacity–TLC The entire volume of the lung, circa 5 liters Vital capacity–VC The maximum volume that can be inhaled and exhaled ThesaurusSeevital capacity
随便看	riva rivaa riv acquisition holdings, inc. rivadavia, bernardino rivage riva-gemfibrozil riva-glyburide riva-hydroxyzine riva-indapamide riva k 20 sr rival rival (disambiguation) rivaled rivaled her in rivaled him in rivaled in rivaled me in rivaled one in rivaled somebody in rivaled someone in rivaled something in rivaled them in rivaled us in rivaled you in rivaless