Vital capacity is sum of
Ans. a (Inspiratory reserve volume, Tidal volume and expiratory reserve volume) (Ref Ganong 23rd/593)Ganong 23rd/Fig. 35-7:# VC = 4700 ml = ERV + TV + IRVRespiratory volumes and capacities for an average young male.MeasurementTypicalDefinitionRespiratory volumes1Tidal volume (TV)500 mlAmount of air inhaled or exhaled in one breath during relaxed quiet breathing2Inspiratory reserve volume (IRV)3000 mlAmount of air in excess of tidal inspiration that can be inhaled with maximum effort3Expiratory reserve volume (ERV)1200 mlAmount of air in excess of tidal expiration that can be exhaled with maximum effort4Residual volume (RV)1200 mlAmount of air remaining in the lungs after maximum expiration; keeps alveoli inflated between breaths and mixes with fresh air on next inspirationRespiratory Capacities5Vital capacity (VC)4700 mlAmount of air that can be exhaled with maximum effort after maximum inspiration (ERV + TV + IRV); used to assess strength of thracic muscles as well as pulmonary function6Inspiratory capacity (1C)3500 mlMaximum amount of air that can be inhaled after a normal tidal expiration (TV + IRV)7Functional residual capacity (FRC) 2400 mlAmount of air remaining in the lungs after a normal tidal expiration (RV + ERV)8Total lung capacity (TLC)5900 mlMaximum amount of air the lungs can contain (RV + VC)Additional Educational points# In a healthy normal adult male, FVC is approximately 5.0 L, FEV, is approximately 4.0 L, and thus, the calculated FEV1/ FVC is 80%.# Obstructive disorders result in a marked decrease in both FVC and FEV1/FVC, whereas restrictive disorders result in a loss of FVC without loss in FEV1/FVC.# FEV1/FVC for obstructive (42%) versus restrictive (90%) patients defines the hallmark measurements in evaluating these two diseases.
Inspiratory reserve volume, Tidal volume and Expiratory reserve volume
Tidal volume, Inspiratory reserve volume and Residual volume
Expiratory reserve volume, Inspiratory reserve volume and Residual volume.
Residual volume, Inspiratory volume, and Expiratory reserve volume.
Respiratory System