special senses: auditory

Question 1

Soundwaves have two components:

Answer 1

1. Frequency (number of waves over time) – perceived as pitch
   ex: high pitch like a whistle= high frequency

2.Amplitude (height of sound wave) – perceived as loudness
shouting= high amplitude

Question 2

structure of ear: pinna

Answer 2

directs soundwaves into the ear canal.

Question 3

structure of ear: ear canal

Answer 3

carries soundwaves to the tympanica
membrane (ear drum). Tympanic membrane vibrates with the same frequency and amplitude as the sound you hear.

Question 4

structure of ear: tympanica
membrane

Answer 4

ear drum

Question 5

structure of ear: Middle ear ossicles

Answer 5

transmit vibrations from the tympanic membrane to the inner ear

Question 6

structure of ear: Malleus

Answer 6

connected to tympanic membrane

Question 7

structure of ear: Stapes

Answer 7

connected to oval window (thin membrane that separates inner ear from middle ear)

Question 8

where do vibrations pass through (MIT)

Answer 8

Vibrations pass from malleus to incus to stapes – and stapes vibrates against the oval window

Question 9

Inner ear: Vestibular apparatus

Answer 9

For equilibrium

Question 10

Inner ear: Cochlea

Answer 10

For hearing

Question 11

inner ear: 3 fluid channels (vtc)

Answer 11

vestibular duct
tympanic duct
these 2 filled with perilymph – similar composition to extracellular fluids)
cochlear duct

Question 12

cochlear duct filled with:

Answer 12

filled with endolymph = similar
to intracellular fluid with high [K+], low Na+

Question 13

what creates waves in the fluids inside the 3 ducts.

Answer 13

Vibration of stapes on oval window

Question 14

Cochlear duct and tympanic duct are separated by

Answer 14

basilar membrane which plays a role in the coding of pitch

(think CT basel membrane)

Question 15

Cochlear duct: Tectorial membrane

Answer 15

waves in perilymph of vestibular
duct cause this membrane to move and bend hair cells

Question 16

Cochlear duct: hair cells

Answer 16

non-neural mechanoreceptor cells for hearing

Have stereocilia (hair-like structures) that are embedded in tectorial membrane (range in different heights)

Question 17

tallest stereocilium is called the

Answer 17

klinocilium

When stereocilia are physically bent in the direction of the klinocilium by movement of tectorial membrane or basilar membrane, signal transduction occurs and they release
neurotransmitter onto the primary auditory neurons

Question 18

Labelled line coding likely determines

The frequency of action potentials to the brain, determines

Answer 18

pitch

sound intensity (loudness).

Question 19

conductive hearing loss

Answer 19

-Sounds cannot be transmitted (conducted) through the middle ear

Question 20

conductive hearing loss cause

Answer 20

Ear canal plugged with earwax or foreign object

Fluid in or damage to middle ear that prevents middle ear ossicles from vibrating

Question 21

what happens in conductive hearing loss

Answer 21

Makes sounds louder in the the affected ear.

Hair cell receptors and cochlear nerve still intact and and can detect soundwaves through vibration of the
bones of the skull in which the cochlea is embedded

Sounds are not dulled by other ambient sounds, as they would be if sound was being conducted through
the middle ear

ex: covering one ear while talking stimulates conductive hearing loss

Question 22

central hearing loss

Answer 22

Results from damage to nerve pathways leading to the auditory cortex (rare)

Makes sounds louder in the the unaffected ear since there is no transmission of signals into the cortex

Question 23

Sensorineural hearing loss

Answer 23

Results from damage/death to hair cells

causes:
-aging
-Chronic exposure to loud noises
- Makes sounds louder in the unaffected ear since there
is impaired transmission of signals from receptors to the neurons they stimulate

Question 24

Vestibular apparatus

Answer 24

provides information
about movement and position of the body.

Question 25

Vestibular apparatus consist of… (sus)

Answer 25

Saccule, Utricle (Sense linear movements and head position)

and Semicircular canals sense rotational movements (help
you keep balance when spinning)

Question 26

Each structure in the vestibular apparatus contains

Answer 26

hair cells (similar to those in the cochlea) that are activated
as a result of change in position and/or movement Sense linear movements and head position