Download The Human Ear and Hearing

The Human
Ear and Hearing
Initial experiments on the
frequency sensitivity of the
human ear.
Color-coded ~ three regions
How the Ear Works
Part I:
Sound waves
enter the ear
canal and vibrate
against the
tympanic
membrane.
How the Ear Works
Part II: Sound passes through the tympanic membrane,
vibrates the tiny bones of the ear, and is translated to a
nerve impulse through the cochlea. The cochleus, in
turn, sends sound impulses to the temporal lobe of the
brain. The ear is also responsible for the sense of
balance, which occurs within the vestibular apparatus.
The vestibular apparatus translates information about
the body's position to the brainstem.
The physics of
transmitting sound
• sound wave
vibrations in the
air
• into solid - bones
• into liquid cochlea
• to the nerve
#VIII
• to the brain
Parts and more parts…
Parts is parts…
1.
Helix - The in-curve rim of the
external ear
2. Antihelix - A landmark of the
outer ear
3. Lobule - A landmark of the outer
ear. The very bottom part of the
outer ear
4. Crest of Helix - A landmark of
the outer ear
5. ExternalAuditory Meatus - or
External Auditory Canal. The
auditory canal is the channel
through which the sounds are led
from the ear outside to the
middle ear.
Parts is parts…
6. Eardrum - (tympanic membrane) A
thin layer of skin at the end of the
external ear canal
7. Auditory Ossicles - The three small
bones in the middle ear, know as the
hammer (malleus), anvil (incus) and
stirrup (stapes) which are connected
to one another. Together these
ossicles are called the ossicular
chain. Their purpose is to lead the
sound striking the eardrum further
into the inner ear
8. Oval Window - An opening in the
bone between the air filled middle
ear cavity and the fluid filled inner
ear, and is covered by a thin
membrane
Parts is parts…
9. Cochlea - Part of the inner ear that
contains part of the hearing organs.
10. Semicircular Canals - Part of the
organ of balance that is part of the
inner ear
11. Eighth (VIII) Nerve - Nerve that
transmits messages from the inner
ear to the brain.
12. Eustachian Tube - A tube
connecting the middle ear cavity
and the pharynx (back of the throat).
It can be opened by coughing or
swallowing, though it is normally
closed. The occasional opening of
the Eustachian tube is necessary to
equalize the are in the middle ear
cavity
The middle ear
Three Bones of the Ear
The ear ossicles are the smallest bones in the human
body and are housed within the tympanic cavity.
They are named for their distinctive shapes -- malleus
(hammer), incus (anvil), and stapes (stirrup).
The dime placed next to them gives you a perspective
of the size of the bones.
The inner ear
Cochlea
Organ of Corti
Ear Infections
Ear infections of
the outer, middle,
and inner ear
See the interactive ear
http://www.hearingcenteronline.com
The Interactive Ear
The Interactive Ear