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maintaining the body’s balance. As you can see in Figure 4.33 "The Vestibular System", the
vestibular system includes the semicircular canals and the vestibular sacs. These sacs connect
the canals with the cochlea. The semicircular canals sense the rotational movements of the body
and the vestibular sacs sense linear accelerations. The vestibular system sends signals to the
neural structures that control eye movement and to the muscles that keep the body upright.
Figure 4.33 The Vestibular System
The vestibular system includes the semicircular canals (brown) that transduce the rotational movements of the
body and the vestibular sacs (blue) that sense linear accelerations.
Experiencing Pain
We do not enjoy it, but the experience of pain is how the body informs us that we are in danger.
The burn when we touch a hot radiator and the sharp stab when we step on a nail lead us to
change our behavior, preventing further damage to our bodies. People who cannot experience