A&P II Lab: Lung Volumes

tidal volume

the volume of air breathed in and out without conscious effort

inspiratory reserve volume

the additional volume of air that can be inhaled with maximum effort after a normal inspiration

expiratory reserve volume

the additional volume of air that can be exhaled after normal exhalation

vital capacity

the total volume of air that can be exhaled after a maximum inhalation

VC = TV + IRV + ERV

how do you calculate vital capacity

residual volume

the volume of air remaining in the lungs after maximum exhalation (the lungs can never be completely emptied)

total lung capacity

is equivalent to VC + RV

minute ventilation

the volume of air breathed in 1 minute: (TV)(breaths/min)

spirometry

a valuable tool for analyzing the flow rate of air passing into and out of the lungs; used to diagnose pulmonary conditions

respiratory cycle

a single inspiration followed by a single expiration

maximal inspiration

results from contraction of the diaphragm downward and the movement of the ribs upward and outward, both of which expand the chest cavity

forced expiration

the result of the rapid contraction of chest and abdominal muscles, as well as the relaxation of the diaphragm

flow volume loop

lung flow rates are graphed as this; airflow is graphed as a function of volume

terminal bronchioles

the latter part of the expiration curve represents the emptying of these small airways

restrictive disorders

include any disease that affects the expansion of lung tissue resulting in a reduction in vital capacity

obstructive disorders

diseases that interfere with the patency of airways resulting in an increase in airflow resistance; forced expiratory volumes are used to assess these

forced vital capacity

the total exhaled air from a maximum inhalation to maximum exhalation

forced expiratory volume

the volume of air expelled in the first second of a forced exhalation

peak expiratory flow

the highest point on the exhalation graph