And how to know if you need one! While it gets lost easily in the noise of the WIC, the truth is that the wedding is the ceremony, and the reception is the party that happens after the wedding. In a similar way, the rehearsal dinner has become a big deal in the American Wedding Machine, and the rehearsal itself is often an afterthought.
Residual volume (RV) is a lung volume representing the amount of air left in the lungs after a forced exhalation; this volume cannot be measured, only calculated.
The diaphragm also contracts to extend the cavity further downwards. Due to the function of the pleural membrane, the size of the lungs is increased which, in turn, creates an area of lower air pressure inside the lungs; hence, air is drawn into the lungs. Exhalation is the process of expelling air out of the lungs. For this to occur, the air pressure inside the lungs must be higher than that of the external atmosphere as air flows from areas of higher pressure to ones of lower pressure.