QS Study

Residual Volume is the volume of air remaining in the lungs utter the most forceful expiration. It is the volume of air still remaining in the lungs after the most forcible expiration possible and amounting usually to 60 to 100 cubic inches called also residual air; compare supplemental air.

Amount: 1200 ml. (In men 1.2 L. women 1.1 L). On average, a person’s RV is about a liter and doctors can run particular tests to find a person’s RV, as it can specify lung health.

Fig: Residual Volume

Importance – Residual volume is the amount of air left in the lungs at the end of a maximal expiration and is naturally increased due to the incapacity to compulsorily terminate and eliminate air from the lungs. It is the only lung volume that is not decreased with respiratory muscle weakness.

  1. It provides air in the alveoli to areate the blood even between breaths thereby, prevents the sudden rise and fall of oxygen and carbon dioxide conc. in the blood in each respiration.
  2. It prevents the collapse of alveoli of lungs.
  3. Provides air to alveoli and maintain gas exchange between breaths.