RESPIRATION 391 



Breathing movements 



Inspiration (increases chest cavity). 



(1) Diaphragm contracts and lowers (vs. abdominal organs). 



(2) Rib muscles raise ribs (vs. elastic cartilage). 



(3) Air pressure expands cells (vs. elastic walls). 

 Expiration (decreases chest cavity). 



(1) Abdominal organs push diaphragm upward. 



(2) Rib cartilages spring back. 



(3) Lung cells contract. 



Rate, 16-24 per minute, depends on age, activity, etc. 

 Air changes in breathing. 



Air contains 



Before inspiration After inspiration 



79 % Nitrogen 79 % 



20.96% Oxygen 16.02% 



.04 % Carbon dioxide 4.38 % 



traces Water vapor .60 % 



little Heat much more, 



none Organic impurities considerable. 



Blood changes in lungs. 



Just the reverse of the above. 



Blood gains 4 to 5 % oxygen. 

 Blood loses about same amount carbon dioxide. 



Blood loses water vapor, heat, organic waste. 

 Ventilation. 



Large amount of air used. 



Importance of oxidation. 



Need for ventilation to supply oxygen. 



to remove heat, water vapor, carbon dioxide. 



