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62 Cards in this Set
- Front
- Back
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What are the two sensory organs housed in the Inner Ear
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~ Hearing
~ Balance |
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What are the functions of the Inner Ear?
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~ Capture Freq
~ Formulate Neural Code vid transducers ~ Sending information from the balance organs to the Central Nervous system |
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What is a labyrinth
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~ Generic name for the middle ear
~ Includes semi-circular canals, Vestibules and Cochlea. |
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What is/where is the Bony Labyrinth
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Series of cavities in the petrous portion of the temporal lobe
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3 main portions of the lony labyrinth
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~ Vestibules (balance)
~ Semi-circular Canal (Balance) ~ Cochlea (hearing) |
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In what body section in the inner ear is the balance organ housed?
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Semi-circular Canal
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In what body section of the inner ear is the hearing organ housed?
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Cochlea
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What is the Cochlea
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Anatomic home for the hearing organ
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What are the two openings of the bony cochlea (on the middle ear wall)?
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~ Oval Wall (vestibuli)
~ Round Window (tympani) |
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What is in the Bony Labyrinth?
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~ Bony shell that contains tissues and fluids.
~ Membranous labyrinth and parilymph |
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What is/Where is that membranous labyrinth?
What is inside of it? |
~ Fluid filled mebranous sac that rests within the cavity of the bony labyrinth.
~ Filled with Enolymph and the organ tissues for hearing and balance |
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What are the two primary inner ear fluids?
How are they different? Which are each located? |
~ Perilymph: High Sodium, Low Potaassium, between the walls of the BL and ML.
Made in the scala vestibuli and scala tympani Endolymph: Low Sodium, High Potassium, Inside the ML. Located within the Scala Media |
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What is the cochlear Aqueduct?
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Opening of the temporal bone. Allows communication between the parilymph and cerbral spinal fluid.
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What is the modiolus?
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Bony structure core of the cochlea
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What is the modiolus structural signifigance?
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Perferated bone, nerve fibers leave the scala media and exit preforations to form the auditory nerve, and follow to the the brain.
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What is the Osseous spiral Lamina?
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~OSL
~ Bony tissue shelf protruding from the modiolus, ~ attachedment for scala media in the basilar membrane |
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3 ducts/ channels in the cochlea
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~ Scala Vestibuli
~ Scala Media ~ Scala Tympani |
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What is the helicotrema
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Where the Scala vestibuli and the scala tympani "communicate" with each other.
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What fluids are in each of the three scala?
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~ Perilymph - Scala Vestibuli, Scala Tympani
~ Endolymph - Scala Media |
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What is the Vestibule opening form the middle ear to the inner ear?
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Oval Window
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What is perilymph?
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Cushion fluid between the membraneous and bony labyrinths
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Source of Perilymph?
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~ CPS,
~ and may secrete thru the spiral ligamint. |
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Where does endolymph come from?
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Stria Vascularis
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Where/how does it go back to?
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Leaves the scala cascularis (during hearing) and flowa thru the cilia of the hair cells (space below the techtorial membrane and above reticular lamina) the left overs loop back to the stria vasularis.
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What is/Where is corilymph?
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Inner ear fluid. found in the tunnel of corti and in the space surrounding the base of hair cells
(Corilymph may be a form of perilymph, but no one is sure.) |
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What is the chemical composition of earch of the three inner ear fluids?
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~Perilymph: High Sodium (NA), Low Potassium (K)
~ Endolymph: Low sodium (NA), High Potassium (K) ~ Cortilymph: High Sodium, Low potassium |
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What are the hair cells and what is their function.
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~ Most important sensory transducers
~ Transform fluid into energy ->electrical singnal that can be interpreted by the brain. |
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Differences between the outer and inner hair cells?
(OHC) |
OHC:
12000, 5-10% are afferent Vulerable to trauma Active (helps IHC) Can test them Low intensity sounds |
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Differences between the outer and inner hair cells? (IHC)
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IHC:
3500 90-95% afferent Less vulerable to trauma Inactive/Passive No direct testing for them |
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Stereocilia cross links? Effect on the hair cells
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Fiberous Protien structures that tie the cilia together which allows for uniform movement. (pic)
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What is distinctive able the Tectorial Membrane?
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It is gelatinous (between solid and fluid), which allows for less impedance for max energy flow
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What are the two functions of the Tectorial Membrane
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~ Protect the inner hair cells from severe wave action
~ Cases bending effect (different physically then Basiliar membrane)Which allows them to vibrate differently. |
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Where is Basilar Membrane
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~ Structural Membrane
~ Under the organ of corti, basically rests on top of the BM. ~ Separates scala media from scali tempani |
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What happens to the basilar membrane following exposure to sound
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~ Gets displaced
~ where is gets displaces relys on the Freq of the Vibration, ~ Place of displacement in a Tonotopic Displacement |
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What characterstics of the Basilar membrane contribute to tonotopic organization
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~ Tension
~ Width ~ Thickness |
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On the Basilar membrane, where is the greatest displacement for high frequency stumulus
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~ Basal End
~ depending on how high the Hz is, will depend on how high on the BM the sound will travel |
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On the Basilar membrane, where is the greatest displacement for Low frequency stumulus
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~ Apical End
~ depending on how low the Hz is, will depend on how low on the BM the sound will travel |
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Tectorial membrane and the basilar membrane differences in vibrational characteristics
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~ Bending and Shearing
~ So they can move differently. Two dissimilar media move diffrently depending on the Freq |
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Origin of the otoacustic emission?
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Outer hair cells
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What does it mean if someone doesn't have one (above)?
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At least a mild hearing loss
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What is the major application
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New born hearing screening
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20th Century Scientist credited for cochlear mechanics
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George Von Bekesy
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What is a neuron
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~ Nerve Cell
~ Function unit of the nervous system |
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What are the Parts of a neuron?
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~ Cell Body with a cell nucleus
~ Cytoplasmic extensions (Axons, or dendrites) |
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What is different about the Primary Auditory neurons?
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It is a bipolar neuron
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What is/Where is a ganglion
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a Cell body in the Peripheral Nervous System
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What makes a ganglia different from a nuclei?
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A Ganglia is in the PNS, while the Nuclei is in the CNS
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What is the difference between an afferent (sensor) nerve and an efferent (motor) nerve?
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~ Afferent is connected to peripheral processes
~ Efferent is connected to central processes |
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What are the two types of auditory afferent nerve fibers?
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~ Type 1 (radial)
~ Type 2 (Spriral) |
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To which type of hair cell do the type 1 nerve (radial) fiber attach?
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Attach to the IHC
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To which type of hair cell do the type 2 nerve (spiral) fiber attach?
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Attach to the OCH
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what is meant by many-to-one vs one-to-many connections
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~ Many-to-one: there are many Type 1 neurons connected to one IHC
~ One-to-many: One type 2 neuron connected to many OHC's |
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Through what series of holes in the modiolus do that Auditory nerve fiber exit the organ of Corti and get to the spiral ganglia?
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Habenula Perforata
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Through what hole in the Temporal bone do the Auditory nerve fibers exit to enter into the brain stem?
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Internal Auditory Meatus (IAM)
Or Internal Auditory Canal (IAC) |
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What six structures run in the IAM or IAC?
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~ Cochlear Branch of the CN VIII
~ Inferior Division of the Vestibular Nerve ~ Superior Division of the Vestibular Nerve ~ Cranial Nerve VII ~ Cochlear Artery ~ Cochlear Vein |
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What are the 2 branches of the VIIIth Cranial Nerve?
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~ Cochlear Branch
~ Vestibular Branch |
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What are the 2 branches of the Vestibular Nerve
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~ Inferior Division of the Vestibular Nerve
~ Superior Division of the Vestibular Never |
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How does the auditory system initially encode frequency?
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Pitch
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How does the auditory system initially encode Intensity?
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Loudness
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Describe/Outline the activity which occurs in the cochlea which results in the generation of a neural impulse at the base of the auditory hair cells?
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~ Frequency
~ Neuron Firing |
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How does the auditory system initially encode frequency?
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Pitch
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How does the auditory system initially encode Intensity?
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Loudness
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