Airway resistance is a concept used in respiratory physiology to describe mechanical factors which limit the access of inspired air to the pulmonary alveoli, and thus determine airflow.
Resistance is greatest at the bronchi of intermediate size, in between the fourth and eighth bifurcation.[1]
Because airway resistance is dictated by the diameter of the airways and by the density of the inspired gas, the low density of heliox reduces airway resistance, and makes it easier to ventilate the lungs.
Resistance can be calculated using Ohm's law[2] or Poiseuille's law.[3]
Contents |
Ohm's law
- R = resistance
- P = pressure
= airflow (the dot over the letter is used to denote rate in respiratory physiology.)
Poiseuille's law
(rewrite)
- R = resistance
- n = viscosity
- l = length
- r = radius
Because of the fourth power in the denominator, resistance increases rapidly as diameter decreases.
See also
References
- ^ Physiology at MCG 4/4ch2/s4ch2_51
- ^ Physiology at MCG 4/4ch2/s4ch2_46
- ^ Physiology at MCG 4/4ch2/s4ch2_47
External links
|
||||||||||||||||||||
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
