Outline the differences between a special sensory, motor and mixed cranial nerve, and briefly describe the functions of each sensory component of the cranial nerve What are EPSPs and IPSPs, and how are they produced? Explain how these electrical currents are used in spatial and temporal summation to initiate or inhibit the generation of an action potential Describe how the central nervous system is protected from injury. List the components of a spinal reflex arc. Describe the function of each component.