Lung Volumes and ventilation Flashcards
what is the average total lung capacity?
6L
what is tidal volume (TV)?
The volume of air breathed in and out of the lungs at each breath.
what is the expiratory reserve volume (ERV)?
The maximum volume of air which can be expelled from the lungs at the end of a normal expiration.
what is inspiratory reserve volume (IRV) ?
The maximum volume of air which can be drawn into the lungs at the end of a normal inspiration.
what is residual volume (RV) ?
. The volume of gas in the lungs at the end of a maximal expiration.
what is vital capacity (VC)?
tidal volume + inspiratory reserve volume + expiratory reserve volume. the greatest volume of air that can be expelled from the lungs after taking the deepest possible breath.
what is total lung capacity (TLC)?
vital capacity + the residual volume.
what is inspiratory capacity (IC)?
tidal volume + inspiratory reserve volume
what is functional residual capacity (FRC)?
expiratory reserve volume + residual volume.
FEV1:FVC
Fraction of forced vital capacity expired in 1 second
why is there a residual volume left in the lungs on expiration?
- to prevent alveoli collapsing, if this happened then large amounts of energy would be required to inflate them again
- allows constant gas exchange
what is pulmonary ventilation?
total air movement into/out of lungs per minute (tidal volume *respiratory rate)
what is alveolar ventilation?
fresh air getting to alveoli and therefore available for gas exchange per minute
why is alveolar ventilation different from pulmonary ventilation?
as a result of the dead space above the alveoli (150ml). on expiration this fills with stale air and so on inspiration only 350ml of fresh air reaches the alveoli instead of 500ml.
what is hyperventilation?
when the alveolar ventilation is higher than normal this results from being relaxed.
