IRFP-01
Metro Review
a.
Secondary positioning system consists of
motion- and gravity-sensing organs
b.
The system is redundant; there is one in each
inner ear
c.
Each vestibular apparatus has two structures:
semicircular canals and otolith organs
(1) Semicircular Canals
Superior
Fig 46: Semicircular
Canals
Posterior
Lateral
Figure 46: SEMICIRCULAR CANALS
(a) Each semicircular canal has
three perpendicular tubes
containing fluid and sensory
hairs
(b) As the body moves, the motion
of fluid in the canals provides the
brain with roll, pitch, and yaw
information
(c) When a turn commences, the
inertia of the fluid moves in the
opposite direction relative to the
sensory hairs and we correctly
interpret the turn and its direction
(8-97) Change 2
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