Air Movement
Air enters and exits the lungs through pulmonary ventilation.
Steps in pulmonary ventilation process:
- The diaphragm contracts and moves downward when we breathe in.
- This causes the volume of the thoracic cavity to increase, which according to Boyle's law, decreases the pressure in the cavity. The pressure outside the cavity is greater than inside, so air flows in, trying to equalize the pressure.
- The diaphragm relaxes, moves upward, which decreases the volume of the cavity, increases the pressure, and forces air out.
Terms to know:
Respiratory rate- number of breaths taken in one minute
Respiratory minute volume- amount of air moved each minute
Alveolar ventilation- amount of air reaching alveoli each minute
Resting tidal volume- amount of air moved during single cycle
Residual volume- amount of air left in lungs after max exhalation
Vital capacity- max amount of air moved in and out of lung in single cycle
Total lung capacity- total volume of lungs (vital capacity+residual volume)
Respiratory rate- number of breaths taken in one minute
Respiratory minute volume- amount of air moved each minute
Alveolar ventilation- amount of air reaching alveoli each minute
Resting tidal volume- amount of air moved during single cycle
Residual volume- amount of air left in lungs after max exhalation
Vital capacity- max amount of air moved in and out of lung in single cycle
Total lung capacity- total volume of lungs (vital capacity+residual volume)