Answer:
Cochlea: Hearing
Saccule and utricle: maintenance of static equilibrium
Semicircular ducts and ampulla: maintenance of dynamic equilibrium
Explanation:
Hearing
We hear by funneling sound from the environment into the outer ear and causing
the tympanic membrane to vibrate. Those sound waves vibrations are transferred
into mechanical vibrations of the ossicles. Those mechanical vibrations cause
the oval window to move back and forth causing the perilymph of the inner ear to
begin wave-like motions. The perilymph fluid motion is transferred to the
endolymph and the wave motion is transformed into electrical impulses picked
up by the hairy cells of Corti and sent to the brain via the cochlear nerve. The
round window is responsible for absorbing the fluid wave vibrations and
releasing any increased pressure in the inner ear caused by the wave motion.
Balance
Balance is a choreographed arrangement that takes sensory information from a
variety of organs and integrates it to tell the body where it is in related to gravity
and the earth.
Information from the vestibular system of the inner ear (semicircular canals,
the saccule and the utricle) is sent to the brainstem, cerebellum, and spinal cord.
Potential balance abnormalities do not require conscious input from the cerebrum
of the brain. Abnormal vestibular signals cause the body to try to compensate by
making adjustments in posture of the trunk and limbs as well as making changes
in eye movement to adjust sight input into the brain.
There are three semicircular canals in the inner ear positioned at right angles to
each other like a gyroscope. They are able to sense changes in movement of the
body. With such changes, endolymph waves within the canals cause hair cells
located within their base to move. Position of the head is sensed by hair cells of
the utricle and saccule which is stimulated when the head moves and the
relationship to gravity changes.
