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Flashcards in The Physiology of Hearing Deck (10)
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1

Describe the pathway of hearing

2 parts

Conductive:
-ear canal
-tympanic membrane
-ossicles

Sensorineural:
-cochlea
-cochlear nerve
-auditory cortex

2

How do the cochlea help with hearing?

Hair cells within the Organ of Corti produce electrical activity (endolymph, perilymph)

This activity becomes a neural impulse and travels to the brain via the cochlear nerve VIII

3

Explain the Vestibule and Semicircular Canals and their function

Balance

Semicircular canals:
-Lateral
-Posterior
-Superior
plus saccule, utricle

hair cells and otoconia produce electrical activity

This activity becomes a neural impulse and travels to the brain via the vestibular nerve VIII

4

What two features combine to form sound?

Intensity (loudness)
Frequency (pitch)

5

Describe the clinical significance of sound intensity

0 decibels is the quietest sound you should be able to detect between 18-20

Pain threshold:
-Threshold = 0db
-Pain threshold = 130 db

6

Describe the clinical significance of sound frequency

Speech range is between 500Hz and 2000Hz

8000 outside human range e.g. dogs

Conductive losses tend to predominate in low frequencies

Sensorineural losses tend to predominate in high frequencies

7

What parts of the Cochlea deal with high and low frequency?

Basal turn = high frequency
Apical turn = low frequency

8

What is audiometry?

A subjective test involving the patient and audiologist

Measures amplitude or intensity of sound and frequency

9

What is Tympanometry?

Measure of tympanic membrane compliance involving middle ear and ear canal pressure

Because of Eustachian tube function canal pressure should = middle ear pressure

Useful to detect:
-Eustachian tube dysfunction
-Middle ear effusion (glue-ear)

10

Explain the importance of hearing in children

Key importance of sound input in development of auditory complex. Links to speech cortex.

Children "born" deaf in one ear will grow up with element of auditory cortex "adaptation"

Children born severely deaf will not be able to develop normal speech

If profoundly deaf then even if hearing restores will never speak unless it is achieved before the age of 4