202 



APPLIED PHYSIOLOGY 



contraction of the muscles of breathing which lasts for a few seconds, 

 so that a person cannot catch his breath. 



A substance sucked into the trachea irritates the nerves which go to 

 the respiratory center. The center sends back an order to the respira- 

 tory muscles to expel the substance by a forcible blast of air. Thus 

 the substance is coughed or sneezed up. 



350. Artificial respiration. The walls of the chest are 

 elastic and quickly return to their natural size when they 



are relieved of 

 stress. It is pos- 

 sible, therefore, to 

 imitate natural 

 respiratory move- 

 ments upon a man 

 who has stopped 

 Diagram of artificial respiration, showing inspiration, breathing. This 



The arrows show that the arms are moved outward jg called artificial 

 from the sides of the chest. 



respiration. 



By pressing hard upon the chest fifteen or twenty times 

 a minute, a great deal of air will be made to pass in and 

 out of the chest. 

 A more effective 

 method is to lay 

 the person upon 

 his back, with the 

 head lowest if pos- 

 sible. Standing 

 at his head, draw 

 each arm out- 

 ward and upward, 

 in a semicircle, 



Diagram of artificial respiration, showing expiration. 



The arrows show that the arms are carried directly for- 

 ward until they are pressed hard against the chest. 



away from his body, until they are stretched above his head 

 almost in a line with his body. This raises the chest and 



