Hearing

Question 1

why is hearing important?

Answer 1

communication: hearing is essential to language

Localization: determining the location of unseen sound sources

Question 2

components of the hearing mechanism

Answer 2

1. Outer ear
   Auricle
   External auditory canal
2. Tympanic membrane
   Ossicles
   Malleus
   Incus
   Stapes
   (MIS)
3. Inner ear
   Cochlea
   Cochlear duct
4. Central auditory nervous system (8)

Question 3

tympanic membrane

Answer 3

• Thin membrane
• Forms boundary between the outer and middle ear
• Vibrates in response to sound waves
• Changes acoustical energy into mechanical energy

Question 4

what are the smallest bones within the human body?

Answer 4

ossicles
- housed within the tympanic cavity
- malleus (hammer), Incus (anvil), stapes (stirrups)

Question 5

how does the ear work?

Answer 5

1. Sound waves enter the ear canal and vibrate against the tympanic membrane
2. Sound passes through the tympanic membrane; vibrates the tiny bones of the ear, and is translated to a nerve impulse through the cochlea
3. The cochlea sends sound impulses to the temporal lobe of the bone

Question 6

difference between higher, medium, and lower frequency?

Answer 6

higher frequency: sounds displace the basilar membrane near the base

Medium frequency: sounds displace the basilar membrane near the middle

Low frequency: sounds displace basilar membrane near the apex

Question 7

frequency

Answer 7

tells us how many waves are passing a point per second, the inverse of time

Question 8

wavelength

Answer 8

tells us the length of those waves in meters, almost like a displacement

Question 9

how do hair cells work?

Answer 9

1. Depolarization: pressure of waves of sound displace the bundle of hair-like stereocilia on hair cells in the organ of corti, channels in the hair cell open, allowing positive ions to flow into the cell
2. As depolarization spreads rapidly through the cell
3. Vesicles near the base fuse with the hair cell’s surface membrane
4. Releasing a signaling substance (neurotransmitter) diffusing across the space between the hair cell and a nerve cell that transmits the signal to the brain

Question 10

do hair cells have action or receptor potential?

Answer 10

RECEPTOR POTENTIAL

Influx of positive ions from the endolymph depolarizes the hair cell

Question 11

Bundle of vestibulocochlear nerve

Answer 11

• Travels from the cochlea through the internal auditory meatus to skull cavity and brain stem
• Carry signals from cochlea to primary auditory cortex, with continuous processing along the way

Question 12

Auditory cortex

Answer 12

• Wernicke’s area within temporal lobe of the brain
• Sounds interpreted based on experience/association

Question 13

what are some causes of hearing loss?

Answer 13

1. prescription drugs
2. acoustic trauma
3. bacterial infection
4. hereditary
5. old age

Question 14

What is the function of the middle ear?

a. Transforms sound waves into vibrations
b. Collect sound waves
c. Transmit vibrations to the brain

Answer 14

a. transforms sound waves into vibrations

Question 15

What is the function of the inner ear?

a.Collects sound waves
b. Transforms sound waves into vibrations
c. Transmit vibrations to the brain

Answer 15

c. transmit vibrations to the brain

Question 16

Which part below is NOT a part of the ear?

a. Incus
b. Eardrum
c. Diaphragm

Answer 16

diaphragm

Question 17

Name the 3 bones of the middle ear (auditory ossicles) in order:

Answer 17

Malleus, incus, stapes (MIS)