Lecture 7-3: Lung volumes, dead space, minute ventilation, alveolar ventilation

tidal volume (TV)

• amount of air inhaled or exhaled in one breathing during relaxed, quiet breathing

• typical = 500 ml/breath

residual volume (RV)

• amount of air remaining in lungs after maximum expiration

• typical = 1200 ml/breath

vital capacity (VC)

• amount of air that can be exhaled with maximum effort after maximum inspiration

• typical = 4700 ml/breath

functional residual capacity (FRC)

• amount of air remaining in lungs after a normal tidal expiration

• typical = 2400 ml/breath

minute ventilation V(E) definition and equation

• the total volume of air inhaled or exhaled from the lungs in one minute

• minute ventilation = tidal volume x breathing rate (frequency)

is minute ventilation an accurate measure of air available for gas exchange?

not an accurate measure of air available for gas exchange, as it includes air that never reaches the alveoli (anatomical dead space)

alveolar ventilation definition and equation

• volume of air that reaches the respiratory zone (alveoli) per minute, participating in gas exchange

• V(A) = (TV - V(D)) x frequency

V(D)

• anatomic dead space

• volume of conducting zone of the lungs

• no gas exchange in this space