CSD 373

located in the outer ear, what part of the temporal bone is this?

Choose matching term

1

What dB is the most important for the purpose of this course (used to plot audiograms)

2

Mastoid process of temporal bone

3

Functions of the Eustachian tube:

4

squamous of temporal bone

Don't know?

Terms in this set (91)

Alphabetical

Adult's Eustachian tube

45 degree angle

Child's eustachian tube

flat and 180 degrees

Condensation sound waves

increased air pressure

cone of light

dB HL

- Hearing Level​
- Used to plot audiograms ​

dB IL

Intensity level

dB SL

- Sensation Level​

dB SPL

- Sound Pressure Level ​

Describe the cochlea in the inner ear

High Frequencies at the base and Low Frequencies at the Apex ​

ear canal/external auditory meatus

endolymph

Simliar to intracellular fluid (postive charge) ​

eustachian tube

Frequency theory

Pattern of discharge codes for frequency

Frequency Wavelengths

- Hz
- Cycles / Second
- High vs. low frequency

Functions of the Eustachian tube:

- pressure equalization
- fluid drainage

functions of the inner ear

- movement of the basilar membrane (tonotopic organization)
- Sheering of hair cells
- depolarization

functions of the middle ear

Acoustic Vibrations into Mechanical Vibrations ​

hair bundles/stereocilia

Hair cells

- View with tectoral membrane peeled away. ​
- OHC's are embedded in the tectorial membrane​
- Bending of the stereocilia toward kinocillium creates the action potential inside the hair cell which begins the neural transmission to the brain. ​

Helicotrema

is at the apex of the cochlea. The helicotrema is where two of the three chambers of the inner ear combine (scala vestibuli and scala tympani... high frequency is the first part of hearing to go.

How does the energy change from the middle to the inner ear?

Mechanical Vibrations to Hydromechanical

how is the basilar membrane inside of the cochlea organized?

tonotopically-- high frequencies at base to low frequencies at the apex​

Impedance matching in middle ear

33 dB gain/increase

incus

a small anvil-shaped bone in the middle ear, transmitting vibrations between the malleus and stapes.

inner hair cell characteristics

- 3500 in single row​
- Chalice shaped​
- Centralized nucleus; organelles throughout cell​
- Only Afferent fibers synapse directly on the cell​
Sends a majority of the afferent information to the brain​

inner hair cells

1 row

inner hair cells of organ of corti

Is the Eustachian tube naturally closed or open?

closed

liquid in scala tympani

perilymph

Malleous

the tiny middle ear bone shaped like a hammer.

malleus

a small bone in the middle ear that transmits vibrations of the eardrum to the incus.

manubrium of malleous

Mastoid process of temporal bone

located in the middle ear, what part of the temporal bone is this?

nerve fibers

Organ of Corti

The Organ of corti is the true sense organ for hearing. When I talk about the parts of the organ of corti "inner" means toward modiolus: "outer" means toward stria vascularis. ​
​
Inner hair cells- 1 row​
Outer hair cells- 3 rows​
​
The cells that transmit the neural signal to the cochlea are pictured in orange above. The inner and outer hair cells can be differentiated a few different ways. In this photo you can ID the OHCs by the 3 distinct rows and the IHCs by the single row.

organ of corti

ossicular chain

outer hair cells

- 12,000​
- 3 rows​
- Cylindrical shaped​
- Organelles along outer wall​
- W appearance from the top​
- Contract and elongate in response to basilar movement (cochlear amplifier)​
- Efferent and Afferent fibers synapse directly on the cell​

outer hair cells

3 rows, form a W
active process of cochlea

outer hair cells of inner ear

Pars flaccida

pars tensa

perilymph

- Similar to CSF- high sodium and low potassium​
- Fills the bony portion of the cochlea​

Period in wavelengths

how long it takes to complete one cycle

Petrous part of temporal bone

located in the inner and middle ear, what part of the temporal bone is this?

Phase locking

Neural discharges occur in the same phase as the stimulus- Valid up to 4000Hz ​

pinna

Place theory

Frequency info coded where peak of traveling wave occurs​

Purpose of the acoustic reflex:

- protection
- reduction of distortion of a person's own voice

Rarefaction

decreased air pressure

Reissner's membrane

separates scala vestibuli from scala media

Scala media

which attaches to osseous spiral lamina (bony protrusions from the modiolus which you will see on the next slide) and contains the organ of Corti: Its borders are the basilar membrane and Reissner's membrane. It is bordered by the stria vascularis which provides blood flow, nutrients and electrical charge to the system. This is imperative for proper cochlear function. ​

scala media

Scala tympani

ends at round window and contains perilymph​

scala tympani

scala vestibuli

which scala attaches at the vestibule and is located above Reisner's membrane. This scala is filled with perilymph. ​

scala vestibuli

semicircular canals

spiral ganglion

cell bodies of the auditory nerve that innervates the sensory hair cells

spiral ligament of inner ear

squamous of temporal bone

located in the outer ear, what part of the temporal bone is this?

stapes

stirrup; last of the three auditory ossicles of the middle ear

Stria Vascularis

external wall of cochlear duct composed of mucosa that secretes endolymph

tectorial membrane

temporal bone

bone that forms parts of the side of the skull and floor of the cranial activity. There is a right and left temporal bone.

tunnel of corti

Tympanic membrane

eardrum

tympanic part of temporal bone

located in the outer ear, what part of the temporal bone is this?

Umbo

vestibule of inner ear

Composed of the utricle, saccule, and semicircular canals

Wave forms: 180 degrees out of phase​

Added together= Cancel each other out ​

Wave forms: complex waves

- Two simple waves combine= Complex wave​
- Lowest frequency of complex wave is Fundamental Frequency​

Wave forms: same starting phase

Added together=Increased amplitude​

Wavelength

speed of sound/frequency

What are the 5 divisions of the ear

Outer​
Middle​
Inner​
Auditory Nerve (8th nerve)​
Central Auditory Nervous System​

What are the functions of the outer ear

funnels sound, transfers function ( up to 15-20 dB), protects ear

What color is used for the left ear?

blue

What color is used for the right ear?

red

What dB is the most important for the purpose of this course (used to plot audiograms)

dB HL

What does the inner ear contain?

Cochlea​
Vestibule​
Utricle and Saccule​
Semicircular Canals​
- Anterior​
- Posterior​
- Horizontal​

What is the function of the eustachian tube?

equalizes pressure

What is the normal state of the Eustachian tube

closed

What kind of energy is in the outer ear

acoustic energy

What kind of response is provided from the acoustic reflex in the middle ear?

bilateral response

what liquid is in scala media

endolymph

What liquid is in the scala vestibuli

perilymph

What occurs when two simple waves combine?

they create a complex waveform.​

What occurs when two waveforms have the same starting phase?

they add to one another and result in a waveform with increased amplitude​

What occurs when waveforms are 180 degrees out of phase?

they cancel one another out.

When two simple waves combine they create a _________ waveform.

complex

Where is the auditory nerve?

inner ear
8th nerve