Monday, 4-11-Hearing & Vestibular Senses Physiology (Karius) Flashcards
The scala vestibuli and scala tympani are continuous, fluid-filled compartments (helicotrema connection) and the fluid inside is ___
The fluid inside the scala media is __
Perilymph
Endolymph
Perilymph is most similar to ___
ECF–> High Na, low K
Which membranes create the scala media to isolate it from perilymph?
Basilar and Reissner’s membranes
What is the electrolyte contents of the endolymph (fluid in scala media)?
High K, low Na–> most similar to ICF
The composition of the __ will have a significant effect on the transduction of sound waves into AP’s
Endolymph
The middle ear transmits the sound waves from the air environment of middle ear to the aqueous environment of the __. The ossicles transmit and amplify the sound waves from the tympanic membrane to the __ of the cochlea
Cochlea
Oval window
__ sounds cause the maximum vibration of the basilar membrane CLOSEST to the oval window. I.e., the sound of a picollo
High frequency, short wavelength
___ sounds cause the maximum vibration of the basilar membrane farthest away from the oval window (toward the helicotrema), i,e., a tuba sound
Low frequency, long wavelength
Each hair cell is composed of a distinct arrangement of shorter stereocilia that increase in length. Each stereocilia is connected to another at the top by an extracellular filamentous protein which is known as the __
Tip link
During development, there is a single true cilium known as the ___. It is the tallest of the ‘hairs’ on the hair cell.
Kinocilium
How do hair cells bend?
When sound causes the basilar membrane to vibrate, the connections between the basilar membrane and the tectorial membrane cause the tectorial membrane to move as well
During transduction, if the stereocilia are bent towards the kinocilium, the hair cell ___
Depolarizes
During transduction, if the stereocilia move away from the kinocilium, the hair cell ___
Hyperpolarizes
Bending the hair cells toward the kinocilium opens __ channels that depolarize the cell
K+
-Due to the composition of the endolymph (high K+, low Na+), K+ enters the hair cells and causes it to depolarize. Ca2+ is also involved
In auditory processing in the cochlear nucleus, the __ path starts processing of temporal and spectral features of the sound, i.e., timing and pitch
Ventral
In auditory processing in the cochlear nucleus, the __ path integrates the acoustic information with somatosensory information for localizing the sound, i.e., tells you where the sound came from
Dorsal
The __ generates a map of the intraaural time differences (how the sound arrived at the 2 ears differently). I.e., when a dog barks closest your right ear, the sound will reach the right ear microseconds before it reaches the left ear. This area is located in the pons.
Medial superior olive
The ___ generates a map of the intra-aural intensity differences (how the sound arrived at the 2 ears differently). I.e., when a dog barks closest to the right ear…because the left ear is farther away from the source of the sound, the intensity (amplitude) of the sound is slightly reduced compared to what the right ear detected. This area is located in the pons
Lateral superior olive
The __ (located in the midbrain) suppresses information related to echoes (they interfere with location) and arrives at a final estimation of the sound location on the horizon.
Inferior colliculus
The __ (located in the midbrain) takes the location data from the inferior colliculus and adds the 3rd dimension to it (vertical height) to create the spatial map of the sound’s location
Superior colliculus
The __ has a tonotopic representation of the sounds- more rostral areas are activated by LOW frequency sounds, while caudal areas receive information about high frequency sounds
Primary auditory cortex (A1)
The __ is composed of several different types of areas (Brocas, wernickes, etc.)
Auditory association cortex
The __ has a lot of neurons that detect pure tones while the __, in contrast, has more neurons that are activated by complex sounds
Primary auditory cortex (A1)
Auditory association cortex
Regarding the cochlear nuclei:
___ pathway: the nature of the sound (high, low)
___ pathway: the location of the sound
Ventral
Dorsal
Regarding the superior olive nuclei:
___: differences in time of arrival to the ears
___: differences in intensity
Medial
Lateral
___ is the spatial map of sound (where it is coming from)
___ creates a tonotopic map, beginning to know what the sound is
Inferior colliculus
Primary auditory cortex (A1)
This membrane separates the perilymph from the scala vestibuli from the endolymph in the scale media
Reissner’s membrane
Linear acceleration occurs in which planes?
Vertical or horizontal
Angular acceleration occurs in what plane(s)?
Requires rotation around 1 or more planes
-Can include spin around vertical axis (spin kick), fall forward or backward
Acceleration in the different planes is detected by:
- semicircular canals
- utricle (swelling where all 3 canals connect)
- saccule (below the utricle)
Where is endolymph and perilymph found in the vestibular apparatus?
- Endolymph (high K+) inside the semicircular canals (anterior, posterior, lateral), utricle, and saccule
- Perilymph (high Na+) surrounds the vestibular apparatus
___ is best situated to detect linear motion occurring on the horizontal plane, i.e., walking
Utricle
___ is best situated for vertical (up and down) accelerations
Saccule
A turning motion is best detected by the ___
Horizontal (lateral) canals
Falling (or being thrown backwards) maximally activates the ___
Posterior semicircular canal
Falling forward maximally activates the ___
Anterior semicircular canal
The process of activating the different vestibular organs is similar to the cochlea-movement of hair cells in 1 direction is excitatory, movement in the opposite direction inhibits. In the semicircular canals, the __ is specialized for this process. In the utricle and saccule (otolith organs), the ___ is specialized for this process
Ampulla
Macula
Motion of the body (particularly the head) will produce motion of the ___ in the appropriate vestibular organ, bending the hair cells inthe ampullae or macula and activating the nerves
Endolymph
If falling forward, the eyes move ___
If falling backward, the eyes move ___
Up
Down
If i fall forward, my eyes move UP to continue to focus as I fall forward and the anterior semicircular canal is activated. Which muscles are active and inhibited?
Superior rectus m.=ACTIVATED
Inferior rectus m.=INHIBITED
If i fall backwards, my eyes move downward and the posterior semicircular canal is activated. Which muscles are activated and inhibited?
Superior oblique m.=ACTIVE
Inferior oblique m.=INHIBITED
If i am spinning, depending on the direction of my turn, the ___ muscles are involved:
Lateral and medial recti muscles
The vast majority of the cortical and cerebellar involvement in the vestibulooptic reflex is to ___
Suppress the reflex to allow for voluntary motion
