1. Taste Smell and Hearing
HCT II

2. 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.

3. 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.

4. 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

6. 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

7. Nose and Sense of Smell (cont)
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

8. 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

9. Very Good! 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!

10. 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

11. 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
Tongue

12. Tongue and Sense of Taste (cont.)
Spicy foods
Activate pain receptors
Interpreted by brain as “spicy”
Taste sensation
4 primary
Sweet – tip
Sour – sides
Salty – tip and sides
Bitter – back
Tongue

13. Back

15. Apply Your Knowledge Great Job!
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. 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

19. 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.

20. 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

21. *** 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?

22. 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

23. Back
Back

24. 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

25. How hearing works

26. The Ear and the Senses of Hearing and Equilibrium: Structures (cont.)
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

27. How to Recognize Hearing Problems in Children
Guidelines
Infants to 4 months
Startled by loud noises
Recognize mother’s voice
4 to 8 months
Regularly follow sounds
Babble at people
8 to 12 months
Respond to the sound their name
Respond to “no”

28. 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

29. 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!

30. 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

31. Infections (otitis):
Otitis Media:
Otitis Externus

32. Otitis Interna

33. Age Related- look the following conditions up and identify the causes, signs and treatments if any.
Meniere's Disease
Otosclerosis

34. Common Diseases and Disorders
Disorder / Disease
Description
Cerumen impaction
Build up of wax within external auditory canal
Hearing loss
Deafness
Meniere’s disease
Disturbance in equilibrium characterized by vertigo and tinnitus

35. 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

36. 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

37. Treating Ear and Hearing Problems (cont.)
Other devices / strategies
Amplifiers
Closed-captioning
Appliances that light up as well as ring
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

38. Apply Your Knowledge Excellent! F 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.
___ Meniere’s disease is characterized by disturbances in equilibrium.
___ Otosclerosis is the immobilization of the stapes.
___ tinnitus is dizziness.
otologist F
externa T
Excellent! F
Tinnitus T T T F
Vertigo