This means that we have a reserve volume that we can tap into as tidal volume increases with exercise or Inspiratory Reserve Volume (IRV): Total lung capacity minus the volume of air in the lung at the end of a normal inspiration. Tidal volume increases with exercise or activity. Tidal Volume (V T): This is the volume of air taken into the lungs when you inhale. Table 1 - Respiratory Volumes and Capacities (approximates which will vary Machines and quickly figure out how to use them! A modern spirometer looks a lot like a little adding machine with a mouthpiece, air tube and a small printout or a cable that feeds data into a computer! There are many brands available,Įach is a little different! One model is displayed below. The bell housing with the paper recording revolved electrically or was driven by a windup mechanism. Working on the assumption that loss of volume of air in the bell housingĬorrelated directly with the volume of CO 2 exhaled and absorbed.

A CO 2Ībsorber could be placed in the bell housing and used in experiments to determine O 2 consumption, Pulleys attach the canister bell to a pen which records volumes on paper on the outside of the canister. The volumes and capacities listed here are normally determined using a spirometer! A traditional 'bell spirometer' is a canister of water with an inverted canister bell over it with air space inside the invertedĬanister bell.

Anatomical dead space tidal vol