Term 
        
        | signal transduction theory |  
          | 
        
        
        Definition 
        
        | a pathway linking mechanical or chemical stimulus to a speific cellular response. |  
          | 
        
        
         | 
        
        
        Term 
         | 
        
        
        Definition 
        
        | a chemical mesenger that influences cells in its vicinity |  
          | 
        
        
         | 
        
        
        Term 
         | 
        
        
        Definition 
        
        | any one of the many cirruculating chemical signals found in all multi-cellular organisms that are formed in specialized cells, travel in body fluids, and coordinate with various parts of the organism by interacting with target cells |  
          | 
        
        
         | 
        
        
        Term 
         | 
        
        
        Definition 
        
        | the taking in of other cells signals to preform its own function |  
          | 
        
        
         |