Learning outcomes Describe the anatomy of the nose and the
function of each part. Describe how smell sensations are created
and interpreted. Describe the anatomy of the tongue and the
function of each part. Describe how taste sensations are created
and interpreted.
Slide 4
Describe the anatomy of the ear and the function of each part.
Explain the role of the ear in maintaining equilibrium. Explain how
sounds travel through the ear and are interpreted in the brain.
State ways that hearing changes with age.
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Introduction Special senses Sensory receptors located in head
Nose smell Tongue taste Eyes vision Ears hearing and equilibrium
Touch is a generalized sense Stimulus nervous system brain
response
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Nose and Sense of Smell Olfactory receptors Chemoreceptors
respond to changes in chemical concentrations Chemicals must be
dissolved in mucus Located in the olfactory organ
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Nose and Sense of Smell (cont) Smell sensation that send the
information along olfactory bulbs and tracts to different areas of
the cerebrum; cerebrum interprets the information as a particular
type of smell Activation of smell receptors information sent to
olfactory nerves
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Nose and Sense of Smell (cont.) Sensory Adaptation Chemical can
stimulate receptors for limited time Receptors fatigue and stop
responding to chemical No longer smell odor Perfume Test
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Apply Your Knowledge ANSWER: After a few minutes, smell
receptors undergo sensory adaptation and no longer respond to the
chemical, and the patient can no longer smell the odor. You notice
an odor coming from a patient when you enter the exam room. Why
would the patient not be able to smell it? Very Good!
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Tongue and Sense of Taste Gustatory receptors located on taste
buds Taste buds Location Papillae of the tongue Roof of mouth Walls
of throat } fewer than on tongue
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Tongue and Sense of Taste (cont.) Taste cells and supporting
structures On taste buds Supporting structures fill in space Taste
cells Chemoreceptors Chemicals in food and drink must be dissolved
in saliva to activate 35-11 Tongue
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Tongue and Sense of Taste (cont.) Taste sensation 4 primary
Sweet tip Sour sides Salty tip and sides Bitter back 35-12 Spicy
foods Activate pain receptors Interpreted by brain as spicy
Tongue
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35-13 Back
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Apply Your Knowledge 35-15 What are the four primary taste
sensations and where are their corresponding taste cells located?
ANSWER: The four primary taste sensations are: Sweet concentrated
on the tip of the tongue Sour concentrated on the sides of the
tongue Salty concentrated on the tip and sides of the tongue Bitter
concentrated on the back of the tongue
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The Ear and the Senses of Hearing and Equilibrium: Structures
External ear Auricle (pinna) Collects sound waves External auditory
canal Guides sound wave to tympanic membrane Contains Cerumen (wax)
Why do we have wax in our ears? Tympanic membrane Separates
external canal and middle ear Vibrates when sound hits it Ear
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Sound waves travel through the external auditory canal to the
tympanic membrane, also known as the ear drum. The tympanic
membrane separates the outer ear from the middle ear. It vibrates
when sound waves hit it and sends those sounds to the middle
ear.
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The Ear and the Senses of Hearing and Equilibrium: Structures
(cont.) Middle ear Ear ossicles Malleus Incus Stapes Ossicles
vibrate in response to vibration of tympanic membrane Eustachian
tube Connects middle ear to throat Equalizes pressure on eardrum
Oval window Separates middle ear from inner ear Ear
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*** Sound waves cause the ear drum to vibrate, which is
amplified or increased by the ossicles. Vibration of the stapes
against the oval window causes movement of fluid in the inner ear.
Auditory or Eustachian tube: This is a tube that connects the
throat to the middle ear. It allows air to enter the middle ear and
equalizes pressure in our ears. Why is it common for an infection
in our throat to spread to our inner ear?
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The Ear and the Senses of Hearing and Equilibrium: Structures
(cont.) Inner ear labyrinth of communicating chambers Semicircular
canals detect balance of the body. This contains a liquid and
delicate hair like cells that bend with movement. Impulses are sent
from the canals to the vestibular nerve and eventually to the
cerebellum of the brain help to maintain our balance. Vestibule
(equilibrium) This acts as a door to the two other parts of the
inner ear. Cochlea 2. Cochlea (shaped like a snail): This contains
hair like cells that line the organ of corti (receptor of sound
waves which carries sound waves from the cochlear nerve to the
auditory nerve.) The auditory nerve carries the message to the
temporal lobe, which interprets the message as hearing. Hearing
receptors Organ of Corti organ of hearing Ear
Slide 24
Back
Slide 25
The Ear and the Senses of Hearing and Equilibrium: Hearing
Process Sound waves collected Waves cause tympanic membrane to
vibrate Ossicles amplify vibrations, which enter inner ear Movement
of hairs lining cochlea trigger nerve impulses Impulses are
transmitted by auditory nerve to the brain for interpretation
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How hearing works
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The Ear and the Senses of Hearing and Equilibrium: Structures
(cont.) Equilibrium Head movement causes fluid in semicircular
canals and vestibule to move Equilibrium receptors transmit
information along vestibular nerves to cerebrum Cerebrum determines
if body needs to make adjustments
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How to Recognize Hearing Problems in Children Guidelines
Infants to 4 months Startled by loud noises Recognize mothers voice
4 to 8 months Regularly follow sounds Babble at people 8 to 12
months Respond to the sound their name Respond to no
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The Aging Ear External ear larger / earlobe longer Cerumen
dryer and prone to impaction Ear canal narrower Eardrum shrinks and
appears dull and gray Ossicles do not move as freely Semicircular
canals less sensitive to changes in position affects balance
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Apply Your Knowledge What problem with the aging ear makes the
elderly more prone to falls? ANSWER: The semicircular canals become
less sensitive to change in position, which affects balance. This
problem with equilibrium results in increased chance of falls in
the elderly. Great Answer !
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Hearing Loss Symptom of a disease, not a normal part of aging
Conductive hearing loss Interruption in transmission to inner ear
Causes Obstruction of ear canal Infection of middle ear Reduced
movement of stirrup Sensorineural hearing loss Sound waves not
perceived by brain as sound Causes Hereditary Repeated exposure to
loud noises / viral infections Side effect of medication
Age Related- look the following conditions up and identify the
causes, signs and treatments if any. Meniere's Disease
Otosclerosis
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Common Diseases and Disorders Disorder / Disease Description
Cerumen impaction Build up of wax within external auditory canal
Hearing lossDeafness Menieres diseaseDisturbance in equilibrium
characterized by vertigo and tinnitus
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Common Diseases and Disorders Disorder / Disease Description
Otitis Otitis externa Otitis media Otitis interna Inflammation of
the ear Swimmers ear Middle ear infection; common infection
Labyrinthitis; inner ear infection OsteosclerosisImmobilization of
the stapes; common cause of conductive hearing loss
PresbycusisHearing loss due to aging process
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Treating Ear and Hearing Problems Patient education
Preventative ear care Administer ear medications Medications and
Irrigation Relieve inflammation or irritation of canal Loosen and
remove impacted cerumen or foreign body
Slide 38
Treating Ear and Hearing Problems (cont.) Hearing aids
Obtaining a hearing aid Otologist medical doctor specializing in
health of ear Audiologist evaluates and corrects hearing problems
Care and use Batteries Routine cleaning Keep dry and avoid hair
sprays Other devices / strategies Amplifiers Closed-captioning
Appliances that light up as well as ring
Slide 39
Apply Your Knowledge True or False: ___ An audiologist is a
physician that specializes in ear health. ___ Otitis media is also
called swimmers ear. ___ Presbycusis is hearing loss due to the
aging process. ___ Vertigo is ringing in the ears. ___ Otitis
interna is an inflammation of the labyrinth. ___ Menieres disease
is characterized by disturbances in equilibrium. ___ Otosclerosis
is the immobilization of the stapes. ___ tinnitus is dizziness. F F
F T T T T F ANSWER: otologist externa Tinnitus Vertigo