The process in which the receptors in the skin turn the stimulation into a neural impulse is called transduction. In addition, transduction is the process by which sensory input is converted to a neural code and sent to the brain. A signal in which a hormone or neurotransmitter interrelates with a receptor on the cell surface in which this contact causes a alteration in a second messenger such calcium and will eventually a alteration is activated in the function of cell.