DSA: Lung Volume & Capacities Flashcards
what is the physiological unit of the lung
alveolar-capillary unit
how does blood from the left heart get to the lungs
-what is its fxn
bronchial A
oxygenated blood to nourish the lungs
what is VT
Tidal Volume
- amount of air inspired/expired in a single breath
- normal = 500 mL
what is RV
Residual Volume
= volume of air that cannot be forced out, no matter how hard you try
(1200 mL)
What is IRV
Inspiratory Reserve Vol
-volume that can be inhaled greater than tidal volume
(measure from VT to max inspiration volume)
(3000 mL)
What is ERV
Expiratory Reserve Vol
-volume that can be exhaled greater than tidal vol
(doesn’t include RV)
(1100-1200 mL)
what is required to achieve ERV
activation of expiratory Ms
What is TLC
& how do you calculate it
maximal volume that lungs can be expanded w/ greatest effort
= IC + FRC
=VC + RV
= ERV + RV + IRV + VT
(5800-6000 mL)
what is FRC
Functional Residual Capacity
air that remains in lungs after normal expiration
= ERV + RV
(2300-2400 mL)
what is the fxn of FRC
prevent collapse of lungs, reduce workload & dilute toxic inhaled gases
What is VC
vital capacity
- volume maximal inspired after maximal expiration
= IRV + ERV + VT
what can influence VC
posture
ability of diaphragm to contract/relax
strength of resp Ms
thoracic wall ability to expand
resistance to air flow
lung elasticity
disease
What is IC
Inspiratory capacity
= air that can be maximally inspired after normal exhale
=IRV + VT
what is normal VT
500 mL
what increases with age
FRC and RV
*FVC decreases*
How do you calculate FRC
