Auditory Senses Flashcards
The Auditory Cortes is located Where?
Temporal Lobe
Place Principle
Nervous system detects SOUND Freq by determining Positions along the Basilar membrane that are midst stimulated
Reissner’s Membrane
- Separates the Scala Media from the Scala Vestibuli
- Maintains a special Fluid in the Scala MEDIA
What Cranial Nerve is for the Auditory system?
8
How much larger is the Tympanic membrane compared to the Stapes
17
What is the Voltage difference between the Endolymph and the Perilymph?
+80mV difference
- Scala Media is POSITIVE
What kind of fibers make up the Auditory nerve?
Sensory Fibers
Organ of Corti
Generates Nerve Impulses in Response to Vibration of Basilar Membrane
Contents of Endolymph
- High [K+]
- Low [Na+]
OPPOSITE to the PERILYMPH
Endolymph vs Perilymph
- Endolymph is inside the Scala MEDIA
- Perilymph is inside the Scala Tympani AND Scala Vestibuli
The major components of the Cochlea
- Scala
- Vestibuli
- Media
- Tympani
2. Reissner’s Membrane (Partition)
Reissner’s Membrane is also known as what?
Vestibular Membrane
Conduction Pathway Sequence
- Tympanic Membrane
- Auditory Ossicles
- Oval Window
Auditory Transmission Pathway Components
- Organ of Corti
- Dorsal/Ventral Cochlear nuclei
- Sup. Olivary Nucleus
- Lateral Lemniscus’ Nucleus
- Media geniculate Nucleus (Thalamus)
- Auditory Cortex
What separates the Scala Media from the Scala Tympani?
Basilar Membrane
Muscles of the Middle ear
- Tensor Tympani
- Stapedius
- Both Contract Reflexively in response to LOUD sound
- > To dampen the vibrations
Stapedius
- Inserts on the Stapes
- Pulls Stapes OUTWARD
Oval Window
- Stapes attaches to the membrane covering the oval window
- Open into the Scala VESTIBULI (Tube)
Tensor Tympani
- Inserts on the Malleus
- Pulls handle of Malleus INWARD
Round window
This membrane covered region is at the end of the SCALA Tympani
What are the 3 Auditory Ossicles
- Malleus
- Incus
- Stapes
What happens to the Basilar fibers as it moves from the Oval window to the Apex of the Cochlea
- Length INCREASES
- Diameter DECREASES
Go from Zu to Mason
Impedance Matching
- Tympanic membrane has 22x force than Cochlea
- Fluid had a greater INERTIA and requires the increase in force in order to cause Vibrations in the fluid
