a&p lab: lung volume

tidal volume

volume of air breathed in & out without conscious effort

inspiratory reserve volume (IRV)

additional volume of air that can be inhaled with maximum effort after normal inspiration

expiratory reserve volume (ERV)

additional volume of air that can be forcibly exhaled after normal exhalation

vital capacity (VC)

total volume of air that can be exhaled after maximum inhalation

VC = TV + IRV ERV

residual volume (VR)

volume of air remaining in lungs after maximum exhalation (lungs can never be completely emptied)

total lung capacity (TLC)

VR + RV

minute ventilation

volume of air breathed in 1 minute

(TV) (breaths/ min)

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what’s spirometry used for

analyzing flow rate of air passing into & out of lungs

maximal inspiration

contraction of diaphragm downward & movement of ribs upward & outward, expanding thoracic cavity

forced expiration

rapid contraction of chest & abdominal muscles, relaxing diaphragm

flow rates are graphed as ___

-in normal lungs: __

-latter portion of expiration curve represents ___

flow volume loops

-in normal lungs: air is rapidly expelled early in the process of forced expiration

-latter part: emptying of small airways (terminal bronchioles)

forced vital capacity (FVC)

total exhaled air, from maximum inhalation to maximum exhalation

forced expiratory volume (FEV1)

volume of air expelled in first second of forced exhalation

FEV1/FVC measured as percentage

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peak expiratory flow (PEF)

highest point on exhalation graph

restrictive disorders

any disease that affects expansion of lung tissue resulting in reduction in vital capacity

*obstructive disorders

diseases that interfere with patency of airways resulting in & increase in airflow resistance

-forced expiratory volumes are used to asses obstructive disorders