The document summarizes how the human ear works to hear sounds and maintain balance. It describes how sound waves enter the ear canal and vibrate the eardrum, causing the tiny bones of the middle ear to vibrate which translates the vibrations into nerve signals sent to the brain. The inner ear's cochlea and vestibular apparatus also help with hearing and balance by sending signals to the brain. The document lists and diagrams 12 key parts of the outer, middle, and inner ear.

1. WELCOME

2. SUBMITTED BY
KEERTHI V S
REG NO. 13303014
NATURAL SCIENCE
MOUNT TABOR TRAINING
COLLEGE,
PATHANAPURAM

3. The Human
Ear and Hearing

4. Color-coded ~ three regions

5. How the Ear Works
Part I:
Sound waves
enter the ear
canal and vibrate
against the
tympanic
membrane.

6. 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.

8. Parts and more parts…

9. 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…

10. 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…

11. 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
Parts is parts…

12. The middle ear

13. 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.

14. The inner ear

15. Cochlea

16. Organ of Corti

17. THANKS