Respiratory Cycle

Respiratory Cycle


This lesson will describe the steps involved in the respiratory cycle.

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Terms to Know

The events that occur to drive air flow out of the lungs; when the diaphragm relaxes and the thoracic cage collapses putting a positive pressure on the lungs driving air out.


The events that occur to drive air flow into the lungs; when the diaphragm contracts to expand the thoracic cage and decrease the pressure inside of the chest.

Respiratory Cycle

The events that occur during one breath; inhalation + exhalation = 1 respiratory cycle.

Tidal Volume

The volume of air we breathe in per breath; the average tidal volume is 500 mL/breath.

Vital Capacity

The maximum amount of air you move during one breathing cycle.