system (ANS). The CNS is made up of the brain and spinal cord. Both the PNS and
the ANS carry information to and from the central nervous system. The PNS is
generally concerned with the innervation of skeletal muscles and other muscles made
up of striated muscle tissue, as well as sensory information from the periphery of the
body. The ANS is that portion of the nervous system concerned with control of smooth
muscle, cardiac muscle, and glands. The CNS (figure 11-4) is known as central
because its anatomical location is along the central axis of the body and because the
CNS is central in function. If we use a computer analogy to understand that it is central
in function, the CNS would be the central processing unit and other parts of the nervous
system would supply inputs and transmit outputs.
Figure 11-4. The human central nervous system.