N4 Auditory And Vestibular Systems Flashcards
Fills perilymphatic space (between bony and membranous labyrinths). Similar to ECF. Continuous with subarachnoid space through cochlear aqueduct.
Perilymph
Fills membranous labyrinth (continuous throughout, closed system). Similar to intracellular fluid.
Endolymph
Cells within the walls of the membranous labyrinth are connected by tight junctions creating a ____ between Perilymph and Endolymph.
Diffusion barrier
Endolymph is secreted by cells within the cochlea called ____. Endolymph flows out through the ____ to the ____ where it is reabsorbed.
Stria Vascularis
Endolymphatic duct
Endolymphatic sac
Auditory and Vestibular Receptors are ___ cells, which are found within the ____. Groups of hair cells, tallest stereocilia project into a _____. Tallest stereocilia are known as ____.
Hair
Membranous labyrinth
Gelatinous mass
Kinocilium
Hair cells are _____ _____ channels.
Stereocilia are ____ (bend at base).
Stereocilia are linked to each other (so they bend as a unit) by _____.
Mechanosensitive transduction
Rigid (actin)
Tip Links
Subtle differences in physical arrangements of hair cells determine the stimuli to which they are most sensitive:
Sound= _____ (structure)
Head movement = _____
Head position = _____
Cochlea
Semicircular ducts
Utricle and saccule
Membrane suspended in perilymph and filled with endolymph. Embedded in temporal bone, forms 2.75 turns.
Cochlea
Peripheral nerve processes of the cochlea are contained within the _____
Osseous Spiral Lamina
The cell bodies (spiral ganglion) are part of this portion of the cochlea:
Modiolus
Central nerve processes of the cochlea are part of this structure:
Cochlear nerve
Sound ____ is determined by the rate and number of nerves firing
Intensity
Basilar membrane and organ of corti (tonotopic organization) detect sound ____
Frequency
Sound ____ is accomplished by comparing stimuli between ears within the CNS
Location
When cochlear hair cells are damaged by VIII endings are intact, _____ are used where electrodes are placed at different points along the ____.
Cochlear implants
Basilar membrane
Primary afferents stimulated by ____ contain their cell bodies in spiral Ganglion and synapse at both the ____ and ____.
Hair cells
Dorsal and Ventral cochlear nuclei
Second order fibers from the dorsal cochlear nucleus ascend in the ____. Second order fibers from the ventral cochlear nucleus synapse at the ____ (by crossing the ___), then ascend through the ____.
Lateral Lemniscus
Superior Olivary Nucleus (involved in sound localization)
Trapezoid body
Lateral Lemniscus
The lateral Lemniscus terminates at the ____, which sends fibers through the inferior brachium to the ____ of the thalamus, which projects to the ____ (primary auditory cortex located on the superior temporal lobe)
Inferior colliculus
Medial Geniculate Nucleus (MGN)
Transverse Temporal Gyri
Regulates posture (erector Spinae muscles), coordinates eye and head movements
Vestibular Division
Each semicircular duct has a dilation called an ____.
Ampulla
A structure of the ampulla. Contains supporting cells and hair cells.
Crista
Creates a partition across the ampulla, responds to angular acceleration (deflection in a perpendicular direction… turning a wheel)
Cupula (gelatinous mass)
Semicircular ducts are not able to detect ____
Continuous rotation
The utricle and saccule each have a tuft of hair cells called the ____. The stereocilia project into a gelatinous mass called the ____, which flops in response to various head positions.
Macula
Otolithic Membrane
Utricle detects these movements
Forward/backward and side/side
Saccule detects these movements
Forward/backward and up/down
The ____ projects directly to the cerebellum and vestibular nuclei.
Vestibular ganglion
Projections out of the vestibular nuclei:
- Spinal cord- posture
- Cerebellum- head movement
- Nuclei of CN III, IV, VI- vestibuloocular reflex (eye movements that keep eye fixed on target when head moves)
- Contralateral vestibular nuclei
- Thalamus -> cerebral cortex- conscious awareness
- Visceral nuclei- autonomic effects
Projections into the vestibular nuclei:
- Cerebellum
- Spinal cord
- Visual Info
- Contralateral vestibular nuclei
Vestibular projections to the spinal cord include:
- Lateral Vestibulospinal Tract- stabilize posture
2. Medial Vestibulospinal tract- stabilize head
Eyes make repetitive uncontrolled movements. Can be physiological (aids in keeping images on the retina during movement) or pathological. Can be slow and fast.
Nystagmus
Excessive alcohol consumption can dislodge the ____ and affect the ____
Otoconia
Cupula
Position Sense depends on these three things:
Need 2 or 3 to function; loss of 2 or 3 will cause disability known as ____
- Vestibular Sense
- Proprioceptive Sense
- Visual Sense
Rhomberg’s sign
