The Special Senses
Lesson 2:
The Senses of Hearing, Taste, Smell
and Touch
Lesson Objectives
Upon completion of this lesson, students should be able to …
 Describe the anatomy of the ear and briefly explain the
function of each structure.
Lesson Objectives
 Describe the anatomy of the nose and explain how the sense
of smell occurs.
 Identify the anatomical structures that make up the special
senses.
 Discuss the sense of taste, and briefly explain the function of
taste buds.
Anatomy of the Ear
Three Main Divisions of the Ear
 External ear
 Middle ear
 Inner ear
Label ear
Structure and Function of the
External Ear
 Pinna, or auricle:
 Funnels sound waves
 Auditory canal, or auditory
meatus:
 S-shaped, secretes cerumen
Structure and Function of the
External Ear
 Tympanic membrane, or eardrum:
 Separates the external ear from the
middle ear
Take a closer look:
 Otoscope
Structure and Function of the Middle
Ear
 Contains : malleus (hammer), incus (anvil),
stapes (stirrup)
 Function
 Transmits sound vibrations
 Equalizes air pressure
 Protects from damaging noise
Structure and Function of the Inner
Ear
 Bony labyrinth :
 Cochlea, vestibule, and three semicircular canals
 Cilia=Tiny hair cells
Structure and Function of the Inner
Ear
 Eustachian tube extends from the middle
ear to the nasopharynx
Hearing test
 http://www.freehearingtest.com/test.shtml
 Or use audiometer
Path of Sound Vibrations
Two Most Common Types of Hearing
Disorders
 Conductive:
Hearing loss can be corrected
 Sensorineural:
Hearing loss cannot be corrected
Four Types of Taste Cells
 Sweet
 Sour
 Salty
 Bitter
The Sense of Touch
 Oldest, most primitive sense
 More nerve endings equals more sensitivity
Medical Specialists
 Ears, nose and throat specialist