How do only certain cells respond to particular signaling molecules that may be sent throughout the body? see section 11.3 ( page 244) . how do only certain cells respond to particular signaling molecules that may be sent throughout the body? see section 11.3 ( page 244) . they express the appropriate second messenger(s). they express the appropriate receptor. they express the ras protein. they express the appropriate g protein?

The answer is ‘They express the appropriate receptor.’ Cells have different receptors on their surface that bind to specific extracellular molecules just as immune cells recognize specific antigens or epitope by use of specific receptors or immunoglobulins. An example is that cells that respond to insulin hormone are those that have insulin receptors. When the receptors have bound these molecules, their resulting conformational change results in activation of secondary messengers inside of the cell.   

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .