Medical Assisting 4e

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31
Special Senses
2
Learning Outcomes

• 31.1 Describe the anatomy of the nose and the
  function of each part.
• 31.2 Describe how smell sensations are created
  and interpreted.
• 31.3 Describe the anatomy of the tongue and the
  function of each part.
• 31.4 Describe how taste sensations are created
  and interpreted.

3
Learning Outcomes (cont.)

• 31.5 Name the four primary taste sensations and
  the acknowledged fifth taste sensation.
• 31.6 Describe the anatomy of the eye and the
  function of each part, including the accessory
  structures and their functions.
• 31.7 Trace the visual pathway through the eye and
  to the brain for interpretation.
• 31.8 Identify ways that patients can practice
  preventive eye care.

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Learning Outcomes (cont.)

• 31.9 State ways that vision changes with age.
• 31.10 List the medical professionals involved in
  diagnosis and treatment of visual disorders,
  including the roles that each play in patient
  care.
• 31.11 List treatments for visual disorders.
• 31.12 Describe the causes, signs and symptoms,
  and treatments of various diseases and conditions
  of the eye.

5
Learning Outcomes (cont.)

• 31.13 Describe the anatomy of the ear and the
  function of each part.
• 31.14 Explain the role of the ear in maintaining
  equilibrium.
• 31.15 Explain how sounds travel through the ear
  and are interpreted in the brain.
• 31.16 State ways that hearing changes with age.

6
Learning Outcomes (cont.)

• 31.17 List the types of hearing loss and how they
  differ.
• 31.18 Describe treatments for ear and hearing
  disorders.
• 31.19 Explain how patients can be educated about
  preventive ear care.
• 31.20 Describe the causes, signs and symptoms,
  and treatments of various disorders of the ear
  and hearing.

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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

8
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

9
Smell Sensation
Activation of smell receptors ? information
sent to olfactory nerves
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
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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

11
Apply Your Knowledge
You notice an odor coming from a patient when you
enter the exam room. Why would the patient not
be able to smell it?
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.
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
13
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

14
Tongue and Sense of Taste (cont.)

• Taste sensation
• 4 primary
• Sweet tip
• Sour sides
• Salty tip and sides
• Bitter back

• Umami
• 5th basic taste
• Glutamic acid
• Spicy foods
• Activate pain receptors
• Interpreted by brain as spicy

15
Back
16
Tongue and Sense of Taste (cont.)

• Taste sensation

Activation of taste cells
Cranial nerves
Gustatory cortex of cerebruminterprets
information
17
Apply Your Knowledge
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
Great Job!
18
Eye and Sense of Sight

• Vision system
• Eyes
• Optic nerves
• Vision centers in the brain
• Accessory structures

• Eye
• Processes light to produce images
• Three layers
• Two chambers
• Specialized parts

19
Eye and Sense of Sight (cont.)

• Outer sclera
• White of the eye
• Protects the eye
• Sense receptors
• Cornea
• Front of eye
• Window that allows light into eye
• Bends light as it enters

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Eye and Sense of Sight (cont.)

• Middle choroid
• Contains blood vessels
• Iris
• Colored part of eye
• Muscle that contracts and relaxes to open or
  close pupil
• Regulates the amount of light that enters the eye

• Ciliary body
• Muscles
• Controls the shape of the lens
• Lens
• Posterior to iris
• Focuses light on retina
• Accommodation

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Eye and Sense of Sight (cont.)

• Inner retina
• Visual receptors
• Rods
• Sensitive to light
• Will function in dim light limited night
  vision
• Do not provide sharp image or detect color

• Cones
• Function in bright light
• Sensitive to color and provide sharp images
• Optic disc optic nerve enters retina

22
Eye and Sense of Sight (cont.)

• Chambers of the eye
• Anterior chamber
• Front of lens
• Filled with aqueous humor nourishes and bathes
  anterior eye
• Posterior chamber
• Behind lens
• Contains vitreous humor maintains shape of
  eyeball and holds retina in place

23
Back
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Visual Accessory Organs

• Eye orbits
• Eye sockets
• Form a protective shell around the eyes
• Eyebrows protect eyes

• Eyelids
• Skin, muscle, and connective tissue
• Blinking
• Prevents surface from drying out
• Keeps foreign material out of eye

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Visual Accessory Organs (cont.)

• Conjunctivas
• Mucous membranes
• Line inner surfaces of eyelids

• Lacrimal apparatus
• Lacrimal glands
• Lateral edge of eyeballs
• Produce tears
• Nasolacrimal ducts
• Medial aspect of eyeballs
• Drain tears into nose

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Visual Accessory Organs (cont.)

• Extrinsic eye muscles
• Six per eye move the eyeball
• Superiorly
• Inferiorly
• Laterally
• Medially

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Visual Pathways

• Eye works like a camera
• Light enters the eye through the lens
• Refraction cornea, lens, and fluids bend light
  to focus it on the retina

Retina convertslight to nerve impulse
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Eye Safety and Protection

• 90 of eye injuries are preventable
• Eye safety practices
• Adequate lighting/handrails
• Pad or cushion sharp edges on furniture
• Toys should be age-appropriate
• Do not mix chemicals
• Proper protective wear
• Goggles
• Sports eye guards

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Apply Your Knowledge

• Matching
• ___ Middle layer of eye A. Lacrimal glands
• ___ Eye sockets B. Aqueous humor
• ___ Control shape of lens C. Retina
• ___ Outer layer of eye D. Sclera
• ___ Anterior chamber E. Vitreous humor
• ___ Tears F. Ciliary body
• ___ Bending of light G. Choroid
• ___ Posterior chamber H. Orbits
• ___ Inner layer of eye I. Refraction

H
F
D
B
A
I
Out of Sight!
E
C
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The Aging Eye

• Eyelids may droop
• Quality and quantity of tears decrease
• Conjunctiva thins and eyes may become dryer
• Cornea yellows, fat deposits around it
• Brown spots on sclera
• Pupils become smaller

• Lens denser and more rigid
• Lens yellows
• Retinal changes vision fuzzy
• Changes in ability of eye to adapt to light
• Impaired night vision
• Decreased peripheral vision depth perception
• Floaters or flashes of light

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Preventing Falls in the Elderly

• Falls can result in fractures of major bones
• Complications of falls can lead to death
• Prone to falling
• Vision problems
• Poor health
• Slower reflexes
• Patient education
• Safety checklist
• Precautions

• Equilibrium problems
• Medication

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Apply Your Knowledge
What vision changes can occur in the elderly
patient?
ANSWER An elderly patient may have difficulty
seeing because of drooping eyelids. Focusing may
be more difficult because less light enters the
eye. He may have difficulty distinguishing colors
due to yellowing of the lens. Vision may be fuzzy
because of changes in the retina. Night vision
can become impaired. The patient may see floaters
or sparks.
Nice job!
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Vision Testing

• Professionals include
• Ophthalmologist medical doctor who is an eye
  specialist
• Optometrist provides vision screening and
  diagnostic testing
• Opticians fills vision prescriptions for
  glasses and contacts

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Vision Screening Tests

• Myopia impairment of distance vision
• Eyeball is too long
• Light focuses anterior to retina
• Snellen chart
• Normal vision
• 20/20

• Hyperopia impairment of near vision
• Eyeball is shorter
• Light focused posterior to retina
• Test using a handheld chart with various sizes of
  print
• Presbyopia
• Impairment due to aging
• Loss of lens elasticity

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Vision Screening Tests (cont.)

• Contrast sensitivity
• Distinguish shades of gray
• Testing
• Pelli-Robson contrast sensitivity chart
• Vistech Consultants vision contrast system
• Detect cataracts or retinal problems before
  sharpness is impaired

• Color vision
• Color-blindness
• May be inherited
• More common in males
• Tests
• Ishihara color system
• Richmond pseudoisochromatic color test
• Difficulties may indicate retinal or optic nerve
  disease

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Apply Your Knowledge
What is the difference between myopia and
hyperopia and what is presbyopia? What effect
does each have on vision?
ANSWER If the patient has myopia, the eyeball is
elongated and light focuses in front of the
retina. She will have difficulty seeing far away.
If she has hyperopia, the eyeball is shorter than
normal and light focuses behind the retina. With
presbyopia, the lens loses elasticity due to
aging, resulting in the inability to see things
close up.
Reyeght!
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Treating Eye Problems

• Delicate organ caution and sterile technique
  necessary
• Patient education on preventive care
• Administration of medications
• Only ophthalmic medications
• Avoid touching dropper or ointment tube to the
  eye

• Eye irrigation
• Sterile solution
• Purpose
• Remove foreign material
• Relieve discomfort

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Common Diseases and Disorders
Disorder/Disease Description
Amblyopia Lazy eye one eye is not used regularly poor depth perception often concurrent with strabismus
Astigmatism Cornea or lens has abnormal shape blurred images
Cataracts Opaque structures in lens prevent light from passing through vision fuzzy
Conjunctivitis Pink eye highly contagious bacterial infection
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Common Diseases and Disorders (cont.)
Disorder/Disease Description
Dry eye syndrome Common problem decreased production of oil in tears
Entropion Inversion of lower eyelid
Glaucoma Increase in intraocular pressure due to a buildup of aqueous humor in anterior chamber
Hyperopia Farsightedness
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Common Diseases and Disorders (cont.)
Disorder/Disease Description
Macular degeneration Progressive disease inadequate blood supply to retina most common cause of vision loss affects people over 50 years
Myopia Nearsightedness
Nystagmus Rapid, involuntary eye movements
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Common Diseases and Disorders (cont.)
Disorder/Disease Description
Presbyopia Loss of lens elasticity develops with age
Retinal detachment Layers of retina separate medical emergency
Strabismus Convergent Divergent Misalignment of eyes Crossed eyes one or both eyes turn inward Wall eye one or both eyes turn outward
42
Apply Your Knowledge
It is okay to use any solution or medication in
the eye?
ANSWER Only medications or solutions
specifically designated for ophthalmic use may be
used in the eyes. Medications not designated for
the eye may be too concentrated or contain
substances that can injure the eye. Solutions
should be sterile and care must be taken not to
contaminate the tip of the dropper or bottle.
Correct!
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The Ear

• External ear
• Auricle (pinna)
• Collects sound waves
• External auditory canal
• Guides sound wave to tympanic membrane
• Tympanic membrane
• Separates external canal and middle ear
• Vibrates when sound hits it

44
The Ear (cont.)

• Eustachian tube
• Connects middle ear to throat
• Equalizes pressure on eardrum
• Oval window
• Separates middle ear from inner ear

• Middle ear
• Ear ossicles
• Malleus
• Incus
• Stapes
• Ossicles vibrate in response to vibration of
  tympanic membrane

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The Ear (cont.)

• Inner ear labyrinth of communicating chambers
• Semicircular canals detect balance of the body
• Vestibule equilibrium
• Cochlea
• Hearing receptors
• Organ of Corti organ of hearing

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Back
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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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Sense of Hearing

• 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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Sense of Hearing (cont.)

• Bone conduction
• Alternative pathway
• Bypasses external and middle ear directly to
  inner
• Useful in determining cause of hearing problem

50
Apply Your Knowledge
Supear!
Matching ___ Pinna A. Organ of Corti ___
Malleus, incus, and stapes B. Cerumen ___ Hearing
receptors C. Ear ossicles ___ Inner ear
D. Tympanic membrane ___ Organ of
hearing E. Auricle ___ Earwax F. Cochlea ___
Eardrum G. Labyrinth ___ Detect balance of
body H. Semicircular canals
C
F
G
A
B
D
H
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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 of 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.
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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

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Hearing Loss (cont.)

• Noise pollution causes damage to sensitive
  cells in cochlea
• Working with the hearing-impaired patient
• Speak at a reasonable volume, in clear,
  low-pitched volumes
• Face the person use hand gestures, if
  appropriate
• Do not overemphasize lip movements
• Have patient repeat message to verify
  understanding
• Treat hearing-impaired patients with patience and
  respect

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Hearing and Diagnostic Tests

• Hearing tests
• Tuning forks differentiate between types of
  loss
• Audiometer measures hearing acuity
• Diagnostic testing
• Tympanometry
• Measures the ability of the eardrums to move
• Detects diseases and abnormalities of the middle
  ear

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Apply Your Knowledge
Identify the types of hearing loss based on the
description below. What can be used to
differentiate between the two?
Answer Conductive hearing loss
Sensorineural hearing loss
A tuning fork is a simple test to distinguish
between types of hearing loss.
Bravo!
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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

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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

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Common Diseases and Disorders
Disorder/Disease Description
Cerumen impaction Build up of wax within external auditory canal
Hearing loss Deafness
Ménière's disease Disturbance 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
Osteosclerosis Immobilization of the stapes common cause of conductive hearing loss
Presbycusis Hearing loss due to aging process
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Apply Your Knowledge
ANSWER
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. ___
Ménière's disease is characterized by
disturbances in equilibrium. ___ Otosclerosis is
the immobilization of the stapes. ___ Tinnitus is
dizziness.
F
otologist
F
externa
T
F
Tinnitus
Excellent!
T
T
T
F
Vertigo
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In Summary

• 31.1 Olfactory receptors, which are the sense
  receptors for the sense of smell, are found in
  the olfactory organ located in the upper part of
  the nasal cavity.
• 31.2 When the olfactory receptors are activated,
  they send information to the olfactory nerves,
  then on to the cerebellum for interpretation.
• 31.3 Gustatory receptors are found on the taste
  buds, which are located on the papillae (bumps)
  of the tongue.

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In Summary (cont.)

• 31.4 Gustatory receptors are chemoreceptors which
  are activated by the chemicals found in food and
  drink as they are dissolved in the mouths
  saliva. The information is brought to the
  gustatory cortex of the parietal lobe of the
  brain for interpretation.
• 31.5 The four primary taste sensations are,
  sweet, salty, sour and bitter. Each has a
  specialized area of the tongue where each taste
  is most pronounced. The fifth recognized taste
  sensation is umami.

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In Summary (cont.)

• 31.6 The eye is composed of three layers. The
  sclera is the outer protective layer and includes
  the cornea. The middle vascular layer is the
  choroid, consisting of the iris, pupil, ciliary
  body, and lens, and is the area of light
  regulation and focusing. The innermost layer is
  the retina containing the rods and cones, the
  optic nerve, and optic disk. This is where the
  nerve impulse is picked up and brought to the
  brain for interpretation. The accessory organs
  are the orbits, eyelids, conjunctivas, lacrimal
  apparatus, and extrinsic eye muscles, all of
  which are protective for the eye.

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In Summary (cont.)

• 31.7 The cornea, lens, and fluids focus light on
  the retina. The retina converts the image into
  nerve impulses, which are transmitted by the
  optic nerve to the brain for interpretation.
• 31.8 Eye safety and injury prevention includes,
  but is not limited to, adequate lighting and
  availability of hand rails, keeping personal and
  sharp items out of reach of children, wearing of
  safety goggles when operating power equipment and
  using chemicals, and not mixing cleaning agents.

67
In Summary (cont.)

• 31.9 Changes in the aging eye include, but are
  not limited to, diminishing fat tissue, decreased
  tear production, thinner and dryer conjunctiva,
  brown spots in the sclera, changes in the iris
  resulting in smaller pupil, lens becoming denser
  and more rigid, as well as lens and retinal
  changes causing fuzziness of vision and
  difficulty distinguishing colors.
• 31.10 Ophthalmologists (M.D.), optometrists
  (O.D.), and opticians are all professionals who
  deal with eye and vision health.

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In Summary (cont.)

• 31.11 All treatments for eye problems include use
  of sterile technique and extreme caution to
  protect the delicate tissues of the eye. Eye
  irrigations and medication installations are
  common treatments. Instruction on these
  techniques will take place in the Drug
  Administration chapter.

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In Summary (cont.)

• 31.12 Common diseases and disorders of the eye
  include amblyopia, astigmatism, cataracts,
  conjunctivitis, hyperopia, myopia and presbyopia.
  More detailed information on the signs, symptoms,
  and treatments for these conditions, as well as
  other common eye disorders, is found in the
  Pathophysiology section of this chapter, directly
  after the AP section on the eye.

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In Summary (cont.)

• 31.13 There are three parts to the ear. The
  external ear includes the auricle or pinna and
  external auditory canal to the tympanic membrane.
  The middle ear begins at the tympanic membrane
  and ends at the oval window and includes the ear
  ossicles. The inner ear is composed of the
  labyrinth and contains the organ of Corti as well
  as perilymph and endolymph, the fluids of
  hearing.
• 31.14 The semicircular canals and vestibule in
  the inner ear function in the equilibrium and
  balance of the body, sending impulses to the
  vestibular nerves, which transmit information to
  the cerebrum for interpretation.

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In Summary (cont.)

• 31.15 The outer ear collects sound waves and
  channels them to the tympanic membrane, which
  vibrates. The vibrations are amplified by the ear
  ossicles and enter the inner ear and cochlea. The
  movements of the hairs in the cochlea trigger
  nerve impulses that are transmitted by the
  auditory nerve to the brain.
• 31.16 Aging causes the eardrum to shrink. The
  joints between the ossicles degenerate so there
  is less freedom of movement, which causes
  decrease in hearing acuity.

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In Summary (cont.)

• 31.17 Conductive hearing loss is the result of
  sound wave transmission interruption, as with
  cerumen impaction and tumors or infections.
  Sensorineural hearing loss is the result of nerve
  damage so that the brain cannot perceive sounds
  waves as sound.
• 31.18 Ear treatments depend on the condition
  being treated, but may include ear irrigation and
  medication installation as well as hearing aids
  and/or surgery for hearing loss.

73
In Summary (cont.)

• 31.19 Preventative ear care includes, but is not
  limited to, routine hearing exams avoiding the
  insertion of small items into the ear canal and
  using care when using cotton swabs. Ear
  protection should be used when exposed to loud or
  prolonged noise. Use medications such as ear
  drops properly and watch for signs of ear or
  hearing problems.

74
In Summary (cont.)

• 31.20 The pathophysiology section on ear and
  hearing diseases and conditions is found at the
  end of the AP section for the ear. Signs,
  symptoms, and treatments of cerumen impaction,
  hearing loss, Ménière's disease, otitis,
  otosclerosis, and other common problems are
  outlined in this section.

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End of Chapter 31
Every closed eye is not sleeping, and every open
eye is not seeing. Bill Cosby