http://www.ck12.org Chapter 1. Human Biology
- Theparasympathetic divisioncontrols internal organs and glands during the rest of the time. It controls
processes like digestion, heartbeat, and breathing when there is not an emergency.
FIGURE 1.81
The woman pictured here is just pretend-
ing to be frightened, but assuming that
she really was scared, think of which
division of the autonomic nervous sys-
tem would prepare her body for an emer-
gency.Have you ever become frightened and felt your heart start pounding? How does this happen? The answer is your
autonomic nervous system. The sympathetic division prepared you to deal with a possible emergency by increasing
your heart rate. The fact that this happened in the blink of an eye shows how amazing the nervous system is.
Vocabulary
- autonomic nervous system (ANS): Division of the peripheral nervous system; controls involuntary activities
not under conscious control, such as heart rate and digestion. - motor division: Division of the peripheral system that carries messages from the central nervous system to
internal organs and muscles. - parasympathetic division: Subdivision of the autonomic nervous system; controls involuntary activities
when there is not an emergency. - peripheral nervous system (PNS): All the nerves in the body that are found outside of the central nervous
system. - sensory division: Division of the peripheral nervous system that carries messages from sense organs and
internal organs to the central nervous system. - somatic nervous system: Division of the peripheral nervous system; controls voluntary, conscious move-
ments. - sympathetic division: Subdivision of the autonomic nervous system that deals with emergencies.
Summary
- The peripheral nervous system consists of all the nerves that are found outside the central nervous system.