Video Transcript
Consider the following activities
and processes: one, dilation and constriction of pupils; two, kicking a ball; three,
breathing; four, digestion; and five, scratching an ear. Which of the following choices
shows the activities or processes controlled by the somatic nervous system? (A) one, three, and four; (B) two
only; (C) two and five; (D) one and three; (E) two and four.
This question asks us about the
somatic nervous system. So to answer this question, we must
recall the function of the somatic nervous system and compare it to the actions
listed.
The somatic nervous system is one
division of the peripheral nervous system. First, the peripheral nervous
system is divided into two main divisions: the sensory and motor divisions. While the sensory division collects
and transmits all sensory inputs, the motor division mediates all motor outputs or
motor responses.
The motor division is further
divided into two divisions: the somatic nervous system and the autonomic nervous
system. These two divisions use distinct
networks of neurons to accomplish distinct tasks. The somatic nervous system controls
the voluntary actions in the body. It transmits impulses coming from
the central nervous system, which includes the brain and spinal cord, to the
skeletal muscles. Since we have control over
performing them or not, these are the movements that we decide consciously, such as
kicking a ball or scratching an ear.
The autonomic nervous system is
responsible for involuntary movement. Autonomic sounds very similar to
automatic, which can actually be a helpful way to remember what the autonomic
nervous system controls. These actions do not need to be
consciously controlled, such as breathing, digestion, and even constriction and
dilation of the pupil.
So to answer this question, we must
identify which activities and processes are voluntarily controlled and therefore
under the control of the somatic nervous system. Therefore, the voluntary actions
controlled by the somatic nervous system are activities number two, kicking a ball,
and number five, scratching an ear.
