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Physiology of ear, nose ,
larynx and pharynx
1
Physiology of the ear
-- hearing & equilibrium
• Hearing— to transform the sound waves as sensation
physical phenomenon to physiological process.
• To maintain body balance mainly by vestibular
system, in conjunction with the visual &
proprioceptive systems, particularly vestibular
system is more important, vestibule respond to
position & change of head in space.
Semicircular canal
stapes
vestibule incus
cochlea malleus
Auricle
Bony
portion
Narrow External
portion auditory
meatus
Cartilaginous
portion Tympanic
membrane
Nasopharyngeal
opening
Anatomic relationship between external, middle and inner ear
vestibule Inner ear
Semicircular canal
canals
Eighth
cranial nerve
Cochlea
Anatomic relationship between the membranous labyrinths
Concept of acoustics and audiology
• Frequency: to be the number of waves per unit of
time, expressing: Hz.
• Loudness: the loudness of a sound is correlated with
the amplitude wave and its pitch with frequency, the
greater the amplitude, the louder the sound and the
greater the frequency the higher the pitch, expressing:
dB(decibel).
• Threshold: the sound intensity audible to the human
is to determine the lowest level.
Sound transmission
• The waves are transformed by ear drum and
auditory ossicles into the fluid of inner ear.
• Impedance: the wave have to hurdle the resistance
during transforming. The impedance incrase with
various material, the waves travel through air at a
speed of 344 m/s, the speed in water is 1428 m/s.
• Only 0.1% acoustic energy is introduce into the
water, 99.9% are reflected back to air when waves
were transformed from air to water.
Vestibular window
Bone
Cochlear window conduction
Cochlear
nerve
Ear
drum Air
Basilar membrane conduction
The route of the transmission of sound from the
outer to the inner ear
Air
• conduction AC
•Bone conduction BC
Functions of the external ear
•A collector of sound
•Conduction of sound
•Judgment of sound source
icus
Tensor malleus
tympanic
muscle
stapes
perilymph
air
External auditory
stapediusmuscle canal
Ear drum
The structure of middle ear
Malleus handle
1.3 Incus long
process
1
1
Drumhead Stapes
footplate
17
The instructure of ossicular chain
The ossicular chain
acts as a system of leavers
1
1.3
The acoustic energy from large area of the drumhead
is transformed to small area but more powerful
movement of small area of the stapes footplate
1
17
Enhancing mechanism of middle ear on
acoustic energy
•The length difference between handle of
malleus and long process of incus =1.3:1
•The area difference between drumhead and
footplate of stapes =17:1
•Above two difference enhance efficiently
acoustic energy 17x1.3=22 multipleª¥
Phases difference between oval window & round window
Normal drumhead Perforated ear drum
Ossicles Ossicles
Oval window Oval window
Basement
Round window Round window membrane
Summary
Enchancing acoustic function of middle ear
• Length difference between manubrium and long
process of incus, area difference between
incus,
drumhead & footplate of stapes, and phases
difference between oval window & round
window,they may rise auditory acuity 47 dB
• By middle ear impedance match, the acoustic
energy in the airborne sound is efficiently
transformed to fluid-filled cochlea.
fluid-filled
Physiological
function of
muscles in
middle ear
Malleus
Incus
Tensor typanic Contraction of tensor
muscle tympanic muscle pull
the manubraium
Stapedius
muscle medially and
decreases the
vibration of the
tympanic membrane,
Drum contraction of
membrane
stapedius muscle pull
Stapes the footplate of stape
out of the oval
window
Functions of Eustachian tube
•Air exchange
–Keeping the air pressure on the 2 sides
of the ear drum equalied
•Excretory
–Draining for middle ear
•Defense
–Preventing for infection
Variany on anatomic difference of between
Eustachian tube infant and adult
Infant Adult
Eustachian tube was obstructed and
secretive otitis media
Hypertrophy of the adenoid Middle ear fluid
Functions of the cochlear
•Conduction:
–the cochlea conducts sound energy from the
oval window to hair cells.
•Sensation:
–the organ of Corti converts sound energy into
endocochlear action potential
Cochlear sound conductive mechanism
Acoustic energy
stapes
cochlea
Basilar turn of cochlea
Organ of Corti
Cochlear sound
sensory
mechanism
Basila membrane
Membrane
cochlear duct
Cochlear nerve passing
Auditory cortex
Inferior colliculus
Lateral lemniscus
Superior olive
Cochlea Cochlear nucleus
Cochlea
Sound conduction and deafness
Outer,
Conductive
middle deafness
ear
Mixed deafness
Sensory deaf
Inner ear
Sensorineural deafness
(cochlear deaf)
Neurous deaf
Cochlear nerve (postcochlear)
Auditory cortex Neurous deaf
Physiology of the vestibular system
The position of semicircular
canals and otolith organ
Superior canal Saccule
Horizontal
canal
Posterior Utricle
canal
•On each side of the head, the semicircular
canals are perpendicular to each other.
•On each side of the head, the utricle & saccule
are perpendicular to each other .
Crista and otolith organ
instructure
Semicircular Vestibul
canal
Saccular
macula
Ampullar
crista
Endolymph Cochlea
sac
Ductus reuniens
Physiology of semicircular canal
• Crista ampulla is the sensory organ of semicircular
canal.
• The semicircular canals respond to angular acceleration,
rotational head causes a movement of the endolymph
within the pair of semicircular canals, then stimulate the
hair cell of ampulla, produces impulse in the vestibular
nerve
Physiologicl function of the otolith organ
• Sac macula is the sensory organ of utricle & saccule .
• Otolith organ is known to be important in orientation
to linear acceleration.
• Movement may causes the otolith organ deflected,
then stimulate the hair cells of macula produce impulse
and transmit to cortex, to control compensatory
movements, it is necessary to maintain an upright,
stable posture. ª¥
Vestibular organ connect to cortex
• Each vestibular nerve terminates in the
ipsilateral four-par vestibular
nucleus( superior,lateral,inferior & medial),
connect to central cortex: 1.thalamus;
2.cerebellum; 3.cranial cortex; 4.brain stem;
5.anterior spinal cord.
Vestibular
Vestibul-thalamus
nerve
Vestibular nucleus
passing
Vestibulo-
cerebellum
Medial
longitudinal Vestibular Inner
fasciculus nerve ear
Vestibulospinal tracts
Equilibrium regulating reaction by
central nerve
Postural adjustment Visual adjustment Orientation in space
failure failure failure
Nystagmus vertigo
unbalance (eye movement)
Vagus nerve exciting Nausea, vomiting, pallor,
sweating, palpitation, so on
Physiology of the nose
•Nose
–External nose
–Nasal cavity
–Sinuses.
•Nasal physiology
–respiratory
–protective
–olfaction
–resonant function
External nose and internal nose
Superior turbinate Frontal sinus
Root of nose Middle turbinate Sphenoidal
sinus
Back
Bridge of nose
of nose Lower turbinate
pex of nose
Columella
Alar
Nares
Schematic of sinuses(front & lateral view)
Frontal sinus
Frontal sinus
Sphenoidal
sinus
Ethmoid sinus
Maxillary
sinus Ethmoid sinus
Physiology of nose
•Respiratory function
–laminar, turbulence flows, physiologic
nasal turbinate cycle
–To filter, warm and humidify the inspired
air.
•Olfactory function.
•Resonant function.
Respiratory function---laminar, turbulence
inspire
expire
Respiratory function---
physiological cycle of nose
Nasal cavity resistance (left)
Nasal cavity resistance (righ
Total resistance
Protective function---blanket
Mucous blanket
Cilium
Epithelium
Protective function, reflecting sneeze
Trigeminal
nerve
Vagal nerve
Protective function---warm,humidify
Vein
Arteriole
Function olfaction
Olfactory
bulb Cortical
olfactory
filament area
Olfactory
bulb
Olfactory
Olfactory region nerve
Olfactory
epithelium
Nasal polyps under nasal speculum
Normal turbinate Nasal polyps
Physiology of pharynx
•Pharynx
–Nasophyarnx Nasopharnx
–Oro-pharynx Oro-pharynx
–Laryn-pharynx
Laryn-pharynx
Physiology of pharynx
•Functions of the pharynx
–Respiration
–Deglutition
–Voice resonance
–Articulation
–Defence
–Middle ear ventilation
Anatomy of the pharynx
Tube orifice
s
Rosenmueller’ fossa
Torus tubarius
Nasopharnx
Adenoid Nasopharyn
Oro-pharynx Palatine
Oropharynx
tonsil
Laryn-pharynx Epiglottis
Larynpharyn
Larynx
•Respiratory function
–Pharynx is respiratory tract
–Warm, humidify and clean, but no
so strong as nose
•Deglutition
–Deglutition is a reflecting movement
voluntary movement of food from the
mouth into the pharynx.
–The passage of bolus through the
esophagus, is an involuntary, reflecting
movement.
Elevation of soft palate Muscles contract Close glottis food
close nasopharyngeal epiglottis cover glottis bolus passes
cavity
Schematic representation of deglutition
•Language formation
–Voice resonance, to change oral cavity,
pharyngeal cavity produce resonance to midify
voice, to chord sympathetic voice.
–Construction of voice, lip, teeth, tongue palate
accord movement, construct various language.
• Defence and protective function
–The pharyngeal muscles reflexly move
vomit, preventing foreign body ingestion.
Regulating middle ear air pressure
•
Schematic presentation
olaterasectionof head Cartilaginous of Palatine muscular
neck Eustachian tube contraction
The Eustachian tube
The Eustachian tube open
when palatine muscular
contraction
•The immune function of pharyngeal
lymphoid tissue
Adenoid
Paratube
tonsil
Lymphoid node of
Palatine retropharngeal wall
tonsil
Lingual tonsil
A view of the nasopharynx
through a nasopharyngeal mirror
Normal nasopharynx Nasopharyngeal malignant tumor
tumo
Physiology of larynx
•Larynx consist of cartilages skeletal,
muscles, ligament, connect tissue and
muci membrane, which structure a cone
form lumina organ.
Anatomy of larynx
Epiglottis Hyoid bone epiglottis
Thyrohyoid Arytenoid
ligament cartilage
Transverse
Thyroid Oblique arytenoid
cartilage arytenoid muscle
muscle
Crico thyroid
Posterior
muscle
crico-arytenoid
Cricoid muscle
cartilage
An indirect-laryngoscope view
of the glottis
Thyroid Vocal cord
cartilage ligament
Arytenoid
cartilage Cricoid cartilage
•Functions of the larynx
–Respiration
–Sound
–Protection
–Laryngeal closure
•Respiratory function
–Glottis is the narrowest part of
respiratory tract.
–The glottis are controlled by abductors
and adductors.
–The glottis become large as inspiration
and become small as expiration.
•Voice function
–Larynx produces sound vibration which are
modified by palatal, tongue and lip movements
to produce speech.
–Including:
•Larynx --- Vibrator
•Lung --- Air energy
•Nose, pharynx, throat, chest --- Resonator
•Lip, teeth, tongue, palatal --- Construction
•Protective function
–There are three major protective function of
larynx, the first is protective to prevent during
swallowing laryngeal closure very much
resembles as sphincter with the true & false
cords, the arytenoid &the aryepiglottis fold
all coming together, “three defence line”ª¥
Schematic of larynx
Epiglottis
Aryepiglottis
Ventricular folds
bands
Ventricular b
Laryngeal
ventricles Laryngeal sin
Glottis
Vocal cord
Vocal cord
Under Cricoid Thyroid
glottis cartilage cartilage
Laryngeal schematic view Schematic view from interior
from behind to frontal Sagittal section of larynx
•Function of laryngeal
closure
–Closure of the larynx also
allows the buildup of
intrathoracic pressure,
important in defecation,
lifting, deliver or straining
for any reason . ª¥
An indirect-laryngoscope view of
the glottis
Normal glottis Glottis cancer
