The Inner Ear Flashcards
A series of tunnels and cavities hollowed out of the Petro us portion of the temporal bone.
The Inner Ear
What two fluids reside in the inner ear?
Perilymph Fluid and Endolymph Fluid
Which fluid in the inner ear is the outer fluid
Perilymph Fluid
Which Fluid in the inner ear is the Inner fluid?
Endolymph Fluid
What is the purpose of the three semi circular canals
Outer portion contains perilymph fluid which protects the membranous Endolymph fluid. The canals detect rotational movement in any direction for balance and equilibrium. They serve no hearing purpose
The meeting place for the semi- circular canals and the stapes footplate and cochlea
Vestibule
The Vestibule contains two membranous sacs from the semi circular canal, what are they?
Utricle (top) and Saccule (below
What fluid is where in the utricle and saccule
Both contain Endolymph fluid inside and Perilymph fluid surrounds the outside of the utricle and saccule
What are the two outer tubes of the cochlea and what fluid do they contain?
Scala vestibuli (top) and Scala Tympani (bottom) both contain Perilymph fluid
What is the smaller triangular tube between the scala tympani and the scala vestibuli, and what type of fluid does that contain
Scala Media and it contains Endolymph fluid
What two tubes in the cochlea meet at the helicotrema?
Scala tympani and Scala vestibuli
What rocks in the oval window in response to the sound waves arriving from ED
Stapes Footplate
What does the Reissners Membrane Separate
The Scala Media and Scala Vestibuli
What does the Basilar’s Membrane separate?
Scala Media from the Scala Tympani
What is the Baislar membrane the base of?
The Organ of Corti
What 3 membranes run the length of the Scala Media?
Reissner’s, Basilar, and Tectoral as well as Organ of corti
The base of the cochlea, nearest the oval window responds to what frequencies
High Frequencies
The part of the cochlea farthest away, at the apex responds to what frequencies
Low frequencies
States there are certain places in the cochlea , the pathways to the brain and the me-oral lobe itself for specific frequencies
Place Theory
States that transmission from neural energy from the inner ear to brain volleys in sequence to accomplish the desired frequency
Volley Theory
States that at or below 1k Hz the place Theory is right and above 1k Hz the Volley Theory is right
Temporal Theory
What makes up the Auditory Nerve (VIII Nerve)
Cochlea Nerves and the Vestibular Nerve
The ganglion unite like a cable forming what?
The Cochlear Nerve and transmits electro chemical energy
In what 2 ways can the Nerve fibers operate
Rest and Fire, there is no in between based on the level of sound. For both loud and soft sounds it gets the same reaction. It cannot be exercised or strengthened as well.
Consists of 30k neural fibers with 92% of these fibers connecting to the inner hair cells and 5% to outer Hair cells
The VIII Cranial Nerve - Auditory Nerve
Afferent Fibers
Transmits from cochlea to brain
Efferent Fibers
Transmit from brain to cochlea
Listens with one ear only, when source of sound is on opposite side the sound has to travel over head to be heard
Far- Ear Effect or Head Shadow effect
The ability to filter out background noise. Can only work if both ears are balanced. Cannot be beneficial if one aided
Binaural Squelch Effect
A combination of similar but not identical signals at the two ears. If presenting one HF tone and a LF tone simultaneously and you hear one combined tone
Binaural Fusion
Refers to the phenomenon that a sound heard with two ears is usually louder than the same sound heard with one
Binaural Summation
What are the 4 types of Presbycusis?
- Sensory
- Central
- Metabolic
- Mechanical
Type of Presbycusis that involves the hair cells and PT exhibits an abrupt HF Loss
Sensory Presbycusis
Type of Presbycusis that creates a mild loss with gradual loss in HF, usually from ganglion cell loss. Poor Discrimination and common in PT with Ateriosclerosis
Central Presbycusis
Type of Presbycusis with HL usually causing a defect in the chemical composition of Endolymph bc of atrophy (drying up) in Stria Vascularis, Flat HL
Metabolic Presbycusis
Type of Presbycusis that results from a change in the stiffness or compliance of the Basilar Membrane or fixation of the stapes. Slowly progressing Loss with sharp changes in HF
Mechanical Presbycusis
An excess of Endolymph fluid, a disorder of the entire inner ear not just the cochlea. Symptoms include, tinnitus, vertigo and HL
Menier’s Syndrome
In a cross section of the cochlea, the minimum number of rows of hair cells you can see is
4
The total number of neural fiber or neurons in the human auditory nerve is about:
30,000
The basilar membrane separates
The scala media and the scala tympani
The scala tympani is filled with:
Perilymph
The base of the cochlea
Begins at the oval window
The fibers of the auditory nerve at the point of maximum stimulation of the basilar membrane, discharge and recover at a rate of approximately:
Up to 1Khz identical to the stimulus freq
Each of the semi-circular canals:
Are oriented at 90 degrees to one another
Contain perilymph and endolymph
Detect positioning and balance
Collections of the nerve fibers are called
ganglia and nuclei
What is the result of tissue and structure damage
Threshold shift
Distortion of perception of frequencies
Disturbance of perception of loudness
A sensorineural HL is due to a disorder in the
Inner ear
A symptom of recruitment is
Intolerance of loud sounds
Malingering is a category of
Non organic loss
Meniere’s syndrome consists of
Tinnitus, vertigo and HL
An organic disorder is when there is damage to
The hearing mechanism
The neural pathways
The brain
Loudness recruitment
Refers to abnormal loudness growth of clients with sensorineural hearing
Tinnitus is
Often managed by HA’s or tinnitus maskers
A characteristic of conductive loss is
A soft spoken patient
What is not a characteristic of a sensorineural loss
Hearing better in noise than quiet
