The diagram provided shows how the
peripheral nervous system and its motor division are divided into their component
parts. What is the primary function of the
somatic nervous system? (A) To transmit information to
muscles that are under voluntary or conscious control and to mediate reflex
actions. (B) To transmit information to
muscles and glands that are not under voluntary or conscious control.
This question is asking us to
recall the function of the somatic nervous system. To answer this question, let’s
review how the motor division of the peripheral nervous system is organized. The motor division of the
peripheral nervous system can be subdivided based on the types of motor
responses. The motor division handles two
types of motor responses: voluntary motor responses and involuntary motor
Voluntary motor responses are made
by choice and require awareness. These motor movements can be as
simple as flipping on a light switch in a dark room. Voluntary motor responses are
carried out by skeletal muscles and use somatic nerves in order to connect the brain
and spinal cord to the skeletal muscles. So voluntary muscles are controlled
by the somatic nervous system.
Involuntary motor responses are
automatic and do not require awareness in order to be carried out. Many of the involuntary motor
responses are executed by smooth muscle and therefore can never be under voluntary
control. An example of this would be
breathing or digestion. While we know we need to perform
these actions, they occur without our awareness. So involuntary muscles are
controlled by the autonomic nervous system.
With this information, we can now
answer the question. The primary function of the somatic
nervous system is to transmit information to muscles that are under voluntary or
conscious control and to mediate reflex actions.