title: Physiology of Respiration
author:  Michael P. Hlastala 
description: <br />"an excellent reference for the student in respiratory therapy and other allied health disciplines. I would also recommend it as a review tool for the experienced practitioner." -- <em>Canadian Journal of Respiratory Therapy</em>
zlib_text: Raintree Steck-Vaughn
  Illustrated
  @
  SCIENCE
  ENCYCLOPEDIA
  Volume
  1.8
  RES - SHR
  M
  - RAINTREE _ -
  STrcrcvn-rctrNl
  PUBLISHERS
  The Steck-Vaughn Company
  Austin, Texas
  
  RESPTRAToRY SySTEM
  Most living organisms change energy that is locked
  in molecules of digested food into a form that can
  be used by the cells. This changing is done in a
  complex process called respiration (see MF,'IABO-
  LISM; RESPtn+rloN). In order to do this, these
  organisms need a way to get oxygen from the air.
  They must also be able to put carbon dioxide, a
  waste product of respiration, back into the air. This
  part of respiration-taking in oxygen and giving
  off carbon dioxide-is called external respiration.
  In human beings and other animals, it is also called
  breathing. The human respiratory system (rEs'par a
  t6r'€ sis'tam) is responsible for carrying out the
  breathing process (see RRnnrurNc).
  Human beings breathe in and out through the
  nose and mouth. tVhen air enters the nose, it is
  warmed and moistened before it enters 