N4 Auditory And Vestibular Systems

Question 1

Fills perilymphatic space (between bony and membranous labyrinths). Similar to ECF. Continuous with subarachnoid space through cochlear aqueduct.

Answer 1

Perilymph

Question 2

Fills membranous labyrinth (continuous throughout, closed system). Similar to intracellular fluid.

Answer 2

Endolymph

Question 3

Cells within the walls of the membranous labyrinth are connected by tight junctions creating a ____ between Perilymph and Endolymph.

Answer 3

Diffusion barrier

Question 4

Endolymph is secreted by cells within the cochlea called ____. Endolymph flows out through the ____ to the ____ where it is reabsorbed.

Answer 4

Stria Vascularis

Endolymphatic duct
Endolymphatic sac

Question 5

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 ____.

Answer 5

Hair

Membranous labyrinth

Gelatinous mass

Kinocilium

Question 6

Hair cells are _____ _____ channels.

Stereocilia are ____ (bend at base).

Stereocilia are linked to each other (so they bend as a unit) by _____.

Answer 6

Mechanosensitive transduction

Rigid (actin)

Tip Links

Question 7

Subtle differences in physical arrangements of hair cells determine the stimuli to which they are most sensitive:
Sound= _____ (structure)
Head movement = _____
Head position = _____

Answer 7

Cochlea

Semicircular ducts

Utricle and saccule

Question 8

Membrane suspended in perilymph and filled with endolymph. Embedded in temporal bone, forms 2.75 turns.

Answer 8

Cochlea

Question 9

Peripheral nerve processes of the cochlea are contained within the _____

Answer 9

Osseous Spiral Lamina

Question 10

The cell bodies (spiral ganglion) are part of this portion of the cochlea:

Answer 10

Modiolus

Question 11

Central nerve processes of the cochlea are part of this structure:

Answer 11

Cochlear nerve

Question 12

Sound ____ is determined by the rate and number of nerves firing

Answer 12

Intensity

Question 13

Basilar membrane and organ of corti (tonotopic organization) detect sound ____

Answer 13

Frequency

Question 14

Sound ____ is accomplished by comparing stimuli between ears within the CNS

Answer 14

Location

Question 15

When cochlear hair cells are damaged by VIII endings are intact, _____ are used where electrodes are placed at different points along the ____.

Answer 15

Cochlear implants

Basilar membrane

Question 16

Primary afferents stimulated by ____ contain their cell bodies in spiral Ganglion and synapse at both the ____ and ____.

Answer 16

Hair cells

Dorsal and Ventral cochlear nuclei

Question 17

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 ____.

Answer 17

Lateral Lemniscus

Superior Olivary Nucleus (involved in sound localization)

Trapezoid body

Lateral Lemniscus

Question 18

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)

Answer 18

Inferior colliculus

Medial Geniculate Nucleus (MGN)

Transverse Temporal Gyri

Question 19

Regulates posture (erector Spinae muscles), coordinates eye and head movements

Answer 19

Vestibular Division

Question 20

Each semicircular duct has a dilation called an ____.

Answer 20

Ampulla

Question 21

A structure of the ampulla. Contains supporting cells and hair cells.

Answer 21

Crista

Question 22

Creates a partition across the ampulla, responds to angular acceleration (deflection in a perpendicular direction… turning a wheel)

Answer 22

Cupula (gelatinous mass)

Question 23

Semicircular ducts are not able to detect ____

Answer 23

Continuous rotation

Question 24

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.

Answer 24

Macula

Otolithic Membrane

Question 25

Utricle detects these movements

Answer 25

Forward/backward and side/side

Question 26

Saccule detects these movements

Answer 26

Forward/backward and up/down

Question 27

The ____ projects directly to the cerebellum and vestibular nuclei.

Answer 27

Vestibular ganglion

Question 28

Projections out of the vestibular nuclei:

Answer 28

1. Spinal cord- posture
2. Cerebellum- head movement
3. Nuclei of CN III, IV, VI- vestibuloocular reflex (eye movements that keep eye fixed on target when head moves)
4. Contralateral vestibular nuclei
5. Thalamus -> cerebral cortex- conscious awareness
6. Visceral nuclei- autonomic effects

Question 29

Projections into the vestibular nuclei:

Answer 29

1. Cerebellum
2. Spinal cord
3. Visual Info
4. Contralateral vestibular nuclei

Question 30

Vestibular projections to the spinal cord include:

Answer 30

1. Lateral Vestibulospinal Tract- stabilize posture

2. Medial Vestibulospinal tract- stabilize head

Question 31

Eyes make repetitive uncontrolled movements. Can be physiological (aids in keeping images on the retina during movement) or pathological. Can be slow and fast.

Answer 31

Nystagmus

Question 32

Excessive alcohol consumption can dislodge the ____ and affect the ____

Answer 32

Otoconia

Cupula

Question 33

Position Sense depends on these three things:

Need 2 or 3 to function; loss of 2 or 3 will cause disability known as ____

Answer 33

1. Vestibular Sense
2. Proprioceptive Sense
3. Visual Sense

Rhomberg’s sign