The document discusses the anatomy and physiology of the human ear. It describes the ear as having three main parts: the outer, middle, and inner ear. The outer ear collects sounds and directs them through the external auditory canal to the tympanic membrane. The middle ear contains three small bones called ossicles that transmit vibrations from the tympanic membrane to the inner ear. The inner ear converts these vibrations into neural signals for hearing and maintains balance. The cochlea and vestibular system within the inner ear work together to provide hearing and equilibrium.

1. By –
PARITA JAYSWAL

3. ANATOMY AND
PHYSIOLOGY OF THE
EAR

4. Divided into “3” parts:-
1. Outer Ear
2. Middle Ear (Tympanic cavity)
3. Inner Ear

5. MajorDivisionsoftheEar
Peripheral Mechanism CentralMechanism
Outer
Ear
Middle
Ear
Inner
Ear
VIII
Cranial
Nerve
Brain

8. 
It consist of the auricle (Pinna) &
External acoustic meatus ( Auditory
canal)

9. Pinna Landmarks
Helix
Antihelix
Concha
Tragus
IntertragalNotch
Antitragus

10. Auricle (Pinna):-
 It is visible part of ear
 It composed of fibro elastic
cartilage convered with skin.
 Helix- it is outer ridge part
 Lobule (Ear lobe) –Soft pliable
part

11. External acoustic meatus( Auditory canal)
• Slightly “S” Shaped tube
• About 2.5 cm long ( 1 inch )
• External from auricle to tympanic
membrane
• There numerous sebaceous and sweat gland
& hair follicles
• Numerous gland are modified sweat gland
that secret cerumen (Earwax)
• Foreign materials are prevented from
reaching TM by wax, hair and curvature.

12. Tympanic membrane
(Eardrum):-
Thin membrane
It is Oval shaped
Forms boundary
between outer and
middle ear
Vibrates in response to
sound waves
Changes acoustical
energy into mechanical
energy

13. Mastoid Process of
Temporal Bone
Bony ridge behind the
auricle.
Hardest bone in body ,
protects cochlea and
vestibular system.
Provides support to the
external ear and posterior
wall of the middle ear
cavity.
Contains air cavities which
can be reservoir for
infection

14.  Collect sound
 Localization
 Resonator
 Protection
 Sensitive (earlobe)

15. d
This is irregular shaped air
fille cavity.
1 Malleus
2 Incus
3 Stapes
6- Eustachian Tube

16. The Ossicles
Ossicular chain = malleus, incus &
stapes
Malleus (It is Hammer shaped bone)
TM attaches
Incus (It is Anvil shaped bone)
Connector function
Stapes ( It is a Stirrup shaped bone)
Smallest bone in the body
Footplate inserts in oval window on
medial wall
Focus/amplify vibration of TM to smaller
area, enables vibration of cochlear
fluids

17. Eustachian Tube
(Pharyngotympanictube) (“The
Equalizer”)
Mucous-lined, connects middle
ear Cavity to nasopharynx
“Equalizes” air pressure in
middle ear
Normally closed, opens under
certain conditions
Closing of the Eustachian tube
protects the middle ear from
unwanted pressure fluctuations
and loud sounds.

19. Conduction
Conduct sound from the outer ear to the inner ear
Protection
Creates a barrier that protects the middle and inner
areas from foreign objects
Transducer
Converts acoustic energy to mechanical energy
Converts mechanical energy to hydraulic energy
Amplifier
Transformer action of the middle ear

20. The inner ear contain the organ of hearing & balance
It consist of – 1. bony labyrinth
2. Membraneous labyrinth

21. BONY LABIRINTH
IT CONTAINS PERILYMPH
Vestibule:
•Expanded part nearest to middle ear.
•Oval & round window in lateral wall

22. Cochlea –
•Snail-shaped organ with a series of fluid-filled
tunnels; converts mechanical energy into electrical
energy
•Cochlear duct is passes through it and its
triangular in shape which contains specialized
cochlea hair cell.(it helps in hearing)

23. Semi circular canal:
3 tubes continue with vestibular structure
•It is situated on posterior part of bony labyrinth.
Three parts: 1.anterior canal
2. Posterior canal
3. lateral canal.
•Thick part is called ampulla

24. MEMBRANEOUS LABYRINTH
It contains endolymph.
Vestibule:– contains utricle and saccule
Cochlea:- cross section of cochlea have 3
compartments.
1. Scala vastibuli : originate at oval window
2. Sacala tympani : ends at round window.
[two compartments are continous with
each other]
3. Scala media (cochlear duct)

25. 23
Cochlear duct / scala media
Organ of Corti

The end organ of hearing; contains
stereocilia and hair cells,auditory receptors

27. 22
Oval Window – located at the footplate
of the stapes; when the footplate
vibrates, the cochlear fluid is set into
motion
Round Window – functions as the pressure
relief port for the fluid set into motion
initially by the movement of the stapes in the
oval window

28.  Convert mechanical
sound waves to
neural impulses that
can be recognized by
the brain for:
Hearing
Balance

29. PHYSIOLOGYOFHEARING






Sound waves enter pinna travel through auditory canal
Sound waves strike tympanic membrane causing
vibrations (mechanical energy)
Vibrating TM causes ossicles to vibrate
Vibrating stapes bone at oval window generates
movement of cochlear fluid (Hydralics)
Fluid movement stimulates cilia- lined cochlea
Cilia sends electrical impulses along auditory nerve to
brain for interpretation

30. Sound waves & vibration
from air travels [332mtr/sec]
enters in pinna
O1
Through auditory canal it
goes and cause vibration in
Tympanic membrane.
O2
Tympanic membrane
vibration transmitted and
amplify middle ear by
ossicle movements
O3
Stapes bone moves to
and fro in oval window.
O4
Fluid waves transmitted:
perilymph & endolymph
into cochlear duct
O5
It stiimulate auditory
receptors O6
Nerve impulses generate &
pass to brain by 8th cranial
nerve and reaches to hearing
areaof cerebrum and sound
preserved.
O7

31. Flowofear:-

32. PHYSIOLOGY OF BALANCE

33. 01
Any change in head
position cause
movement in perilymph
and endolymph
02
Stimulate sensory nerve
endings In utricle,
saccule and ampullae.
03
Nerve impulses transmit by
vestibular nerve which join
cochlear nerve and forming a
vestibulo-cochlear nerve.
04 Impulses passes to
vestibular nucleous and
then reach to
cerebellum.
05
Impulses from sensory
receptors, skeletal
muscles and joints also
pass from crebrum and
skeletal muscles.
06 Results in awareness of body
position. Maintain postures and
independently head
movements.
PHYSIOLOGY
OF BALANCE

34. BLOOD SUPPLY & NERVE SUPPLY
NERVE SUPPLY:
Nerve Supply By 8th Cranial Nerve
Auditory Nerve
BLOOD SUPPLY:
Internal Auditory Artery And Its
Branches Provide Pure Blood And
Internal Auditory Vein Collects Impure
Blood To Internal Jugular Vein.

35.  Hearing
 Sound Conduction and Transmission
 Balance and Equilibrium