Chapter 52 Flashcards Preview

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Flashcards in Chapter 52 Deck (16)
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1
Q

Which window does the stapes push on?

A

Oval window

2
Q

What muscle (mainly) contracts to attenuate loud sounds?

A

Stapedius

3
Q

What are the three tubs that make up the Cochlea?

A
  • Scala Vestibule
  • Scala media
  • Scala tympani
4
Q

What separates the vestibuli and the tympani?

A

-Reissner membrane

5
Q

What separates the tympani and the media?

A

the basilar membrane

6
Q

What is found within the basilar membrane?

A

Organ of corti

7
Q

What is the tonotopy, or layout of frequency sensitivity in the choclea as distance from the stapes increases?

A
  • As disnace from the stapes increases:
  • frequency decreases
  • High frequency is heard at the base and low frequency at the helicotrema
8
Q

How does bending of the stereocilia towards the larger stereocilia result in depolarization?

A
  • bending of the smaller cilia towards larger ones results in tugging of the smaller cilia out of the hair cell surface
  • tugging on these tip links opens channels for K+ to influx from the surrounding scala and depolarize the hair cell
9
Q

How is frequency determined?

A

Tonotopy: stimulation of hair cells near the base of the cochlea indicate a high pitch sound while stimulation of the hair cells at the apex indicate a low pitched sound

10
Q

How is loudness determined?

A
  • The higher the amplitude the more the basilar membrane vibrates, and the more the hair cells excite the nerve endings
  • spatial summation allows for better judgement of loudness
11
Q

What are the two principle methods used to determine sound direction?

A
  1. lag time between ears
  2. difference in intensities between ears
12
Q

When does the lag time method of direction determination work best? How about intensity differences?

A
  • frequencies below 3000Hz
  • Higher frequencies
13
Q

What is nerve deafness?

A

-impairment of the cochlea, auditory nerve, or CNS

14
Q

What does it mean when someone has conduction deafness?

A

The cochlea is intact but the structures that conduct the sound to the cochlea are not.

15
Q

What type of sound is lost in old age deafness? (air conduction or bone conduction)

A

-Both air conduction and bone conduction of the higher frequencies

16
Q

What type of conduction is affected in middle ear sclerosis? At what frequencies?

A

-exclusively air conduction at lower frequencies