Vestibular System

Question 1

Inner ear is called the ____

Answer 1

labyrinth

Question 2

Osseus Labyrinth components (3)

Answer 2

Cochlea
Vestibule
Semicircular Canals

Question 3

Membranous Labyrinth Components (4)

Answer 3

Cochlear duct
Utricle
Saccule
Three semicircular ducts

Question 4

Endolymph is high in

Answer 4

Potassium

Question 5

Perilymph is high in

Answer 5

Sodium

Question 6

Vestibule

Answer 6

Large chamber adjacent to the middle ear

Question 7

Semicircular canals

Answer 7

Three semicircular channels in bone, each is orthogonal to the other two

Question 8

Cochlea

Answer 8

spiral chamber that is related to hearing

Question 9

Membranous Labyrinth contains:

Answer 9

endolymph

Question 10

Cochlear duct

Answer 10

Related to hearing

Question 11

Utricle

Answer 11

Larger of 2 sacs within the vestibule

Contains Otolith membrane and macula

Question 12

Saccule

Answer 12

Smaller of 2 sacs within the vestibule

Contains otolith membrane and macula

Question 13

3 semicircular ducts

Answer 13

Each have an ampulla which contains a crista ampullaris and a cupulla

Question 14

Crista Ampullaris

Answer 14

crest bearing sensory receptor cells

Question 15

Cupulla

Answer 15

Gelatinous membrane

Question 16

The Vestibular Apparatus Consists of (3)

Answer 16

Macula of the utricle
Macula of the saccule
Crista ampullaris

Question 17

Macula of the utricle

Answer 17

Horizontally oriented and detects LINEAR ACCELERATION in the horizontal plane (side to side)

Question 18

Macula of the saccule

Answer 18

Detects LINEAR ACCELERATION in the vertical plane (up and down)

Question 19

Crista ampullaris

Answer 19

1 in each semicircular duct ampulla

Detects ANGULAR ACCELERATION directed along the plan in which the duct is positioned

Question 20

Movement of the overlying otolith membrane results in deflection of ______

Answer 20

Sterocilia

Question 21

Deflection TOWARD the kinocilium mechanically opens ion channels. This allows ______ to flow from endolymph into the hair cell, thus _______ the receptor cell membrane

Answer 21

Potassium

Depolarizing

Question 22

Depolarization of the receptor cell enables _____ influx and release of ______ from synaptic vesicles which are located along the basolateral region of the receptor cell. The ______ neurotransmitter triggers action potentials in afferent axons on the vestibular nerve.

Answer 22

Calcium

Glutamate

Question 23

Deflection away from the Kinocilium _____ ion channels and ultimately _____ glutamate release

Answer 23

Closes

Reduces

Question 24

In the crista ampullaris, sterocilia are embedded in a geltanious membraned called a ______

Answer 24

Cupula

Question 25

In the macula, stereocilia are embedded in a gelatinous _______

Answer 25

Otolith Membrane

Question 26

Otolith membrane contains

Answer 26

Calcium concretions (ear stones)

Question 27

Receptor cells are ______ active and vestibular nerve axons _____ conduct action potentials to the brainstem. Thus the movement of sterocilia results in an ______ or a _____ in the rate of spontaneous activity.

Answer 27

Spontaneously Continually Increase Decrease

Question 28

Vestibular nerve fibers (axons from the neuronal cell bodies of the vestibular ganglion) travel from the ___ ___ to the ____

Answer 28

Inner Ear | Brain

Question 29

Vestibular nerve fibers synapse in _____ _____ of the brainstem and in the ___ or ____ of the cerebellum.

Answer 29

Vestibular Nuclei Nodulus or flocculus

Question 30

Four vestibular nuclei are located bilaterally in the medulla and the pons. The nuclei receive input from the _______ and project to: (4)

Answer 30

Vestibular Nerve 1. Cerebellum (flocculu-nodular lobe) 2. Reticular formation 3. Spinal cord via the lateral vestibulospinal tract activates limb extensor mm via alpa and gamma neurons 4. Neurons controlling eye and neck mm via the MEDIAL LONGITUNDINAL FASCICULUS

Question 31

Eyes are shifted in a direction ____ to the direction that the head is accelerated

Answer 31

Opposite

Question 32

Vestibular nuclei on the right side dominate activity in the ______ Abducens nucleus and _____ Oculomotor nucleus, causing both eyes to move _____

Answer 32

Left RIght Left

Question 33

In general, vestibular nuclei push the eyes _______

Answer 33

contralaterally

Question 34

Extensor muscles are contracted ________ which the head is accelerating

Answer 34

on the side toward

Question 35

Vestibular Syndrom symptoms (3)

Answer 35

Head Tilt Stumbling Nystagmus

Question 36

Slow phase of nystagmus is directed ____

Answer 36

toward the side of the lesion

Question 37

Vestibular nystagmus is generated reflexly by ___ ___ in response to angular accelreration

Answer 37

Vestibular

Question 38

Opticokinetic nystagmus is generated by ____ when focusing on moving objects (e.g. a train passenger focusing on telephone polls)

Answer 38

Cerebral cortex