The Ear
A.3 pt II
Labelling a diagram of the structure of
the human ear
Structures in the middle ear transmit
and amplify sound
• Describe the middle ear.
a. A thin air filled chamber separated from the outer
ear by the eardrum.
• List the bones (ossicles) of the middle ear.
a. Malleus, incus and stapes
• State the job of these bones.
a. Transmit and amplify sound.
• Describe how the middle ear protects you from loud
sounds.
a. The muscles attached to the bones of the middle
ear contract weakening the connection between the bones to
dampen the vibrations.
Sensory hairs of the cochlea detect
sounds of specific wavelength.
• Describe the job of the cochlea.
a. Transfers vibrations into neural signals.
• Explain how the hair cells of the cochlea work.
a. Vibrations resonate with hair bundles of
particular hair cells. These hair bundles are
selective which enables us to hear sounds of
different pitch
Impulses caused by sound perception are transmitted to the
brain via the auditory nerve
• Describe how a vibration travels from a hair
cell to the auditory nerve.
a. The hair cell becomes depolarized and
releases a neurotransmitter across a synapse of
an adjacent sensory neuron. The sensory
neuron sends the message to the brain along
the auditory nerve.
Hair cells in the semicircular canals
detect movement in the head.
• How many semicircular canals are there?
a. 3
• Explain how the brain can detect movement
using the semicircular canals.
a. The canals themselves move with the
head but the fluid inside lags behind. The fluid
flows past the cupula (hair cells embedded in
gel) and the hair cells send the impulse to the
brain.