(6) DSA: Lung Volumes (Rogers) Flashcards
Contraction of inspiratory muscles produces a:
INCREASE in thoracic volume
What are the muscles involves in inspiration?
Diaphragm
External intercostals
Accessory muscles (scalene, sternomastoids, other muscles of head and neck)
What are the muscles that participate in expiration?
(*compress the rib cage)
Abdominals (displace diaphragm)
Internal Intercostals
What is the risidual volume (RV)?
Volume of air that cannot be forced out, no matter how hard one tries
What is tidal volume (Vt)?
The amount of air inspired or expired in a single breath
What is the normal resting tidal volume?
500ml
What is the inspiratory reserve volume (IRV)?
Volume of air breathed above tidal volume
What is the expiratory reserve volume (ERV)?
Volume of air that can be forced out in addition to tidal volume
*DOES NOT INCLUDE RESIDUAL VOLUME
What is the vital capacity (VC)?
Amount of air that can be maximally inspired following a maximal expiration
What is vital capacity influenced by?
Posture
Ability of diaphragm to contract/relax
Strength of respiratory muscles
Thoracic wall expansibility
Resistance to air flow
Lung elasticity
Disease
What is the inspiratory capacity (IC)?
Capacity of air that can be maximally inspired following a normal exhale
What is the functional residual capacity (FRC)?
Amount of air that remains in the lungs following a normal expiration
What is the total lung capacity (TLC)?
Maximal volume to which lungs can be expanded with greatest effort
What are the influences on lung volumes?
Body size
Age
Posture
Sex
Ethnicity
Obesity
Pulmonary disease
What are the nitrogen-washout technique and helium dilution used for?
Used to determine functional residual capacity
What technique is used for measuring residual volume?
Body plethysmography
