Hearing Anatomy + Physiology Flashcards

(49 cards)

1
Q

Another word for hearing is?

A

Audition

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2
Q

Purpose of the ear?

A

To conduct energy

The ear will convert acoustic energy into electrochemical energy so that the brain can process the information

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3
Q

What are the 3 main parts of the ear?

A

Outer Ear

Middle Ear

Inner Ear

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4
Q

Outer Ear Parts

A

Pinna or Auricle - outermost portion of the outer ear

Pinna Transmits sound to the middle and inner ears, and to localize sound

You can hear without the pinna

Lobe or lobule
Concha Cava - entrance to the ear
Outer Ear - air filled

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5
Q

The entire outer ear is comprised of ?

A

Cartilage

Except for the lobule - composed of fat and connective tissue

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6
Q

Medial to the concha cava is the ?

A

EAM

External Auditory Meatus or ear canal

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7
Q

Together, the concha cava + EAM help with what?

A

Transmission of sound to the middle and inner ear

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8
Q

External Auditory Meatus

A

Later 1/3 is made of cartilage

Medial 2/3 forms the bony meatus of the temporal bone

Terminates @ Tympanic Membrane

Contains cilia (small hairs) + cerumen (ear wax)

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9
Q

Cerumen

A

Protects the ear from dryness + intrusion of bugs/other foreign bodies

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10
Q

Tympanic Membrane

A

Boundary b/w the outer and middle ears

Transmits sound to the 3 ossicles or bones (AKA ossicular chain) of the middle ear.

These bones are medial to the TM

Sound enters the Outer Ear and then reaches the TM, setting it into vibration

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11
Q

3 ossicles or bones of the middle ear

A

Malleus, incus, stapes

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12
Q

Ossicular Chain

A

Delivers vibrations to inner ear + helps protect the inner ear from excessively loud vibrations

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13
Q

Middle ear is filled with what

A

Air

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14
Q

Middle Ear Bones: malleus

A

Most lateral point of attachment for the tympanic membrane

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15
Q

middle ear bones: incus (anvil)

A

lies medial

in between the malleus and stapes

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16
Q

Stapes

A

Most medial of the 3 bones - the smallest

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17
Q

Articulation of middle ear bones

A

Malleus + incus articulate by means of saddle joint

will move as 1 unit when the TM vibrates/moves

Stapes - it’s footplate fills the oval window which is a part of the inner ear

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18
Q

2 muscles of the inner ear

A

Stapedius + Tensor Tympani

Both are attached to the ossicular chain

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19
Q

Purpose of the middle ear muscles

A

to damp or reduce the vibration of the ossicular chain

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20
Q

Stapedius (middle ear muscle)

A

O: Bone of the posterior wall of the middle ear

C: Anterior

I: posterior crus of stapes

F: pulls stapes posteriorly to damp/reduce the vibration of the ossicular chain

21
Q

Tensor tympani (middle ear muscle)

A

O: embedded in the anterior wall of the middle ear
C: posteriorly
I: malleus
F: pulls malleus anteromedially to stiffen the entire ossicular chain (damps or reduces vibration)

22
Q

Middle Ear Landmarks - Medial wall

A

Medial wall of the middle ear

1) Oval Window: part of the inner ear. articulates with the footplate of the stapes. allows fluid in inner ear to move

2)round window: inferior to oval window. allows fluid in inner ear to move

23
Q

Middle Ear Landmarks: anterior wall of middle ear

A

Eustachian Tube - brings O2 to middle ear to maintain balance/equilibrium and to balance the pressure in the middle ear with atmospheric pressure

24
Q

Middle Ear Landmarks: posterior wall + floor of the middle ear

A

Mastoid Air Cells: irregularly shaped, hollowed out spaces in the temporal bone. They lighten the weight of the skull + are important in the conduction of sound through bone

25
Inner Ear
Unlike the outer/middle ears, the inner ear is filled with different types of fluids At this point, the acoustic signal is transported through fluid to CN VIII, the Auditory Cranial Nerve, for processing by the barin It is embedded within the petrous portion of the TEMPORAL BONE
26
Inner Ear Landmarks: oval + round windows
Oval + Round Windows - lateral wall of the inner ear. Oval window will vibrate when stapes moves - this action will cause the fluid of the inner ear to be set into motion Semicircular Canals - important for balance/equilibrium. Fluid-filled, line with cilia
27
Inner Ear: Cochlea
Looks like a coiled snail shell Primary organ of hearing
28
What lies within the cochlea?
Scala Vestibuli and Scala Tympani - form two incomplete chambers in the cochlea. They are separated by a bony shelf called the SPIRAL LAMINA The spiral lamina serves as a point of attachment for the scale media which houses the sensory organ for hearing - the organ of Corti
29
Scala Media
Lies within the cochlea separates the scala vestibuli and scala tympani
30
Helicotrema
Within the cochlea (inner ear) Point where the scala tympani and scala vestibuli meet. The scala tympani and scala vestibuli communicate with each other via the helicotrema
31
Basilar Membrane
Lies within the cochlea Forms the floor of the scala media The organ of Corti rests on the basilar membrane Cochlea is filled with fluid
32
Inner Ear - Scala Vestibuli + Scala Tympani, scala media
Scala Vestibuli + Scala Tympani - the type of fluid found in these chambers is PERILYMPH Scala Media - the type of fluid found here is endolymph Acoustic energy moves through the outer/middle ears and is transmitted through these fluids
33
Inner Ear - Organ of Corti
Within the cochlea Housed in the scala media and rests on the basilar membrane contains inner and outer hair cells
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Inner + Outer Hair Cells
Inner hair cells (IHC) and outer hair cells (OHC) respond to different aspects of the acoustic signal
35
Frequency range for the human auditory mechanism
10 octaves, from about 20 to 20,000 Hz Auditory stimuli can range from whisper to rock concert
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Frequency
psychological correlate of pitch Recorded in Hz
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Loudness
psychological correlate of intensity Recorded in decibels
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Hearing Physiology - audiogram
During an audiological evaluation, the audiologist presents tons of different frequencies and loudness levels The results - that is, how the patient responds - is recorded on an audiogram
39
Hearing Physiology
Cochlea is the organ of audition in the inner ear Recall that the outer and middle ear will funnel in sound Sound travels through air in these two parts of the inner Sound travels through fluid-filled inner ear Cochlea changes the auditory signal into neural impulses that are transmitted to the brain for proessing, via CN VII (Auditory Nerve) Being aware that you heard something, and interpreting what you heard, are both processed by the brain - your ear has nothing to do with this!
40
Hearing Physiology IHC + OHC
The organ of Corti contains inner hair cells (IHC) and outer hair cells (OHC). These functioning differently from one another
41
ICH Inner Hair Cells (Organ of Corti)
Respond to different frequencies of an incoming auditory signal. They help the cochlea process complex sound for frequency, intensity, and other temporal aspects
42
OHC Outer Hair Cells (Organ of Corti)
Help regulate hearing sensitivity for less intense (softer) sounds. They will amplify softer sounds that aids in awareness of interpretation
43
Damage to Hair Cells Results in
Permanent sensory hearing loss The most common cause of this loss is from excessive noise exposure - concerts, NASCAR, NFL games and other sporting arenas, hunting, etc. The cochlea is unable to generate new hair cells; therefore, once these cells are damaged, damage is irreversible as the cells cannot regenerate
44
Auditory Signal Traveling to Brain
Auditory information is transmitted from the organ of Corti to the CN VIII Along CN VIII, there are several areas or processing stations that are important in the processing of auditory information 1. Superior Olivary Nucleus 2. Lateral Lemniscus 3. Inferior Colliculus 4. Primary Auditory Cortex Heschel's gyrus and Wernicke's Area
45
Superior Olivary Nucleus
Integrates information received from both ears. This is the first place the auditory system where binaural processing (stereo hearing) is possible
46
Lateral Lemniscus
Important in sound localization
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Inferior Colliculus
Located in the brainstem. Important in the integration and localization of sound
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Primary Auditory Cortex
Located in the temporal lobe Usually the left for most people who are right-handed.
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