Sistema respiratorio

     1                   
2                        
                      
   3                     
                      
 4                       
     5                   
                      
                      
 6                       
                      
    7      8                
                      
   9                     
       10            11       
                      
        12                
                    13    
 14      15          16           
                      
                      
       17     18              
  19                      
 20                       
                      
                      
  21