lung volumes is the amount of air remaining in the lungs after a normal tidal expiration.
the amount of air remaining in the lungs after a normal tidal expiration is the?
lung volumes
the closing capacity (cc) is the volume in the lungs at which its smallest airways, the respiratory bronchioles, collapse. it is defined mathematically as the sum of the closing volume and the residual volume. the alveoli lack supporting cartilage and so depend on other factors to keep them open. the closing capacity is greater than the residual volume (rv), the amount of gas that normally remains in the lungs during respiration, and specifically, after forced expiration. this means that there is normally enough air within the lungs to keep these airways open throughout both inhalation and exhalation. as the lungs age, there is a gradual increase in the closing capacity (i.e. the small airways begin to collapse at a higher volume/before expiration is complete). this also occurs with certain disease processes, such as asthma, chronic obstructive pulmonary disease, and pulmonary edema. any process that increases the cc by increasing the functional residual capacity (frc) can increase an individual's risk of hypoxemia, as the small airways may collapse during exhalation, leading to air trapping and atelectasis.
closing capacity
most people with a normal distribution of airways resistances will reduce their expired end-tidal nitrogen concentrations to less than 2.5% within seven minutes. individuals with high resistance in their airways can take longer than seven minutes to remove all the nitrogen.





























section::::parameters.





























a nitrogen washout can obtain the following parameters:





























bullet::::- closing volume (cv); the amount of air remaining in the lungs when the flow from the lower sections of the lungs becomes severely reduced or halts altogether during expiration as the small airways begin to close.
nitrogen washout