The respiratory system permits the exchange of
oxygen needed for cellular metabolism for carbon dioxide, which is a by-product
of cellular metabolism. This chapter describes the location and function of
the organs of the respiratory system and explains how they contribute to the
overall function of the system (objectives 1-3). Respiratory and nonrespiratory
air movements, respiratory volumes and capacities, and how normal breathing
is controlled (objectives 4-9) are discussed. Gas exchange and transport, and
oxygen utilization by the cell (objectives 10-13) are explained.
There are four events in respiration: (1) exchange
of gas with the external environment, (2) diffusion of gas across the respiratory
membrane, (3) transport of gas to and from the cell, and (4) diffusion of gas
across the cell membrane for utilization of oxygen by the cell. An understanding
of all these events and how they interact is basic to understanding how cells
produce the energy necessary for life.