1. Ms.Anu Sebastian: B.Pharm; M.Pharm
Assistant Professor,
Dept. Of Pharmacology
Nirmala College Of Pharmacy
Muvattupuzha,Ernakulam,Kerala
2. While at rest, a healthy adult averages 12 breaths a minute,with
each inhalation & exhalation moving about 500ml of air into and
out of the lungs.
Spirometer/Respirometer: The apparatus used to measure the
volume of air exchanged during breathing & respiratory rate.
Spirogram: The record of spirometer.Inhalation is recorded as an
upward deflection & exhalation as downward deflection.
The Minute Ventillation(MV): the total vol. of air inhaled &
exhaled each minute.
MV = Respiratory rate * Tidal volume
=12 breaths/min* 500ml/breath
=6 litres/min
3. Tidal Volume: The volume of one breath.,i.e 500ml.
Inspiratory Reserve Volume: It is the additional volume of
air that can be inhaled into the lungs by a forced inspiration
after a normal inspiration.
For adult male : 3100ml
For adult male : 1900 ml
Expiratory Reserve Volume: It is the volume of air that can
be exhaled from the lungs by forced expiration after a
normal expiration.
For adult male: 1200 ml
For adult female: 700 ml
4. Residual Volume: It is the volume of air that remains in the
lungs following a maximal expiration .It can be expelled
only by opening the thoracic caviy.
For Males: 1200ml
For Females: 1100 ml
LUNG CAPACITIES
Lung capacities are combinations of specific lung volumes.
Inspiratory capacity = Sum of tidal volume and Inspiratory
reserve volume.
For males: 500 ml+ 3100 ml=3600ml
For females: 500ml + 1900ml= 2400 ml
5. Functional residual capacity: Sum of residual volume and
expiratory reserve volume.
For Males: 1200ml + 1200 ml= 2400 ml
For Females: 1100ml + 700 ml= 1800ml
Vital Capacity : Inspiratory reserve volume + Tidal volume
+ Expiratory reserve Volume
For Males: 4800 ml
For Females: 3100 ml
Total Lung capacity = Vital capacity + Residual Volume.
For Males: 4800 ml + 1200 ml =6000 ml
For Females: 3100 ml + 1100 ml =4200 ml
