If, when you exhaled, all the air in your lungs escaped you wouldn't receive a substantial amount of oxygen to nurish your lungs or your body for that matter.
residual volume
Functional residual capacity (FRC) is the volume of air remaining in the lungs after a normal exhalation, while residual volume (RV) is the volume of air remaining in the lungs after a maximal exhalation. FRC includes both the expiratory reserve volume and the residual volume, while RV is the volume of air that cannot be exhaled from the lungs.
Functional Residual Capacity (FRC) = Expiratory Reserve Volume (ERV) + Residual Volume (RV)
Residual volume allows gas exchange to go on continuously
The function of residual volume is to keep enough pressure in the lungs to keep them from collapsing.
Residual volume of air is the volume of air remaining in the lungs after maximal exhalation. It is not possible to voluntarily exhale this air, as it helps to keep the lungs inflated and prevents them from collapsing. Residual volume plays a key role in maintaining the oxygen-carbon dioxide exchange in the lungs.
residual (reserve) volume
The volume not included in the vital capacity is the residual volume (RV). Residual volume is the amount of air that remains in the lungs after a maximal exhalation and cannot be voluntarily expelled. Vital capacity, which consists of tidal volume, inspiratory reserve volume, and expiratory reserve volume, measures the maximum amount of air a person can exhale after a deep breath, excluding the residual volume.
To accurately measure residual volume in a container, you can use a graduated cylinder or a measuring cup with clear markings. Fill the container with the substance, making sure it is level with the top. Then, carefully pour the substance into the measuring tool and note the volume. Subtract this volume from the total volume of the container to determine the residual volume.
Residual volume cannot be measured with a spirometer because a spirometer measures the volume of air that can be inhaled or exhaled, but it cannot measure the air that remains in the lungs after maximal exhalation. This leftover air, known as residual volume, is not accessible for measurement since it is trapped in the alveoli and airways. To assess residual volume, other techniques like body plethysmography or gas dilution methods are used.
Residual volume is the air that remains in the lungs after a maximal exhalation. It is considered a type of "stale" or stagnant air that cannot be voluntarily expelled and helps keep the lungs inflated.
It's (RV) = 1.2...