Auditory/Vestibular Apparatus & GSA Intro

Question 1

Fibers that terminate at the caudal colliculus are for which reflex?

Answer 1

The Startle Reflex

Question 2

Fivers that terminate at the auditory cortex are for?

Answer 2

The Primary Auditory Pathway

Question 3

Where do descending pathways of the Startle Reflex go to?

Answer 3

Go to LMNs of skeletal muscles of the limbs

Question 4

The Auditory is for _______ perception of sound.

Answer 4

Conscious perception

Question 5

Trace the Auditory Pathway starting at the cochlear nuclei.

Answer 5

From cochlear nuclei (ipsilaterally and contralaterally)

• -> Caudal colliculi (via Olivary Nuclei)
• -> Medial Geniculate Nuclei (MGN)
• ->Auditory Cortex for conscious perception of sound

Question 6

When sound cannot get from ear to vestibular window due to disease, damage, or obstruction (like an ear infection) is associated with what type of deafness?

Answer 6

Conduction Deafness

Question 7

When sound gets to the vestibular window but cannot be transmitted to the auditory cortex

Answer 7

Sensorineural Deafness

Question 8

Deafness associated with damage to the cochlea, cochlear nerves, central auditory pathway, or auditory cortex

Answer 8

Sensorineural Deafness

Question 9

What is Prebycusis?

Answer 9

Deafness of old age- a type of Sensorineural Deafness

Question 10

Ototoxic drugs can cause what kind of deafness?

Answer 10

Sensorineural Deafness

Question 11

Which type of deafness is reversible?

Answer 11

Conduction Deafness

Question 12

What kind of reflexes are associated with the Vestibular System?

Answer 12

Motor reflexes

Question 13

What is the major goal of the vestibular system?

Answer 13

To maintain a stable orientation in relation to gravity and motion

Question 14

What does the vestibular system sense?

Answer 14

Balance and Acceleration

“The guy in the VEST is a BA (badass)”

Question 15

The Vestibular System is also called what?

Answer 15

Special Proprioception

Question 16

The vestibular system compares the positions of the eyes, limbs, neck and trunk to the position and movement of the _______.

Answer 16

Head

Question 17

Axons of neurons from the utricle, saccule, and semicircular canals form which nerve?

Answer 17

The vestibular nerve

Question 18

What drives the reflexes of the vestibular system to re-orient or balance the body?

Answer 18

The ASYMMETRY of the inputs going from Cranial Nerve 8 to the vestibular nuclei in the hindbrain

Question 19

What 3 locations does info from vestibular nuclei go to?

Answer 19

1. Motor nuclei of CN 3,4, and 6
2. Through the cerebellum
3. Thalamus and then Cortex

Question 20

To control EYE MOVEMENT in response to vestibular movement, signals from the vestibular nuclei are sent where?

Answer 20

To the motor nuclei of CN 3, 4, and 6

Question 21

The ________ receives info from the vestibular nuclei in order to control posture and balance.

Answer 21

Cerebellum

Question 22

The cerebellum carries out 2 reflexes. Name them.

Answer 22

Vestibulospinal Reflex (Trunk stability)
Vestibulocollic Reflex (Head and Neck stability)

Question 23

Describe the vestibular pathway for control of EYE MOVEMENTS

Answer 23

CN8 –> Vestibular Nuclei–> Via Ascending MLF–> CN-3,4,6

This is bilateral, ipsilateral and contralateral

MLF= Medial longitudinal fasciculus in the brainstem

Question 24

Describe the vestibular pathway for control of POSTURE and BALANCE

Answer 24

CN8–> Vestibular Nuclei–> Cerebellum–> MVT or LVT

MVT: medial vestibulospinal tract- Bilateral
LVT: lateral vestibulospinal tract- Ipsilateral

Question 25

Describe the vestibular pathway for conscious perception of movements

Answer 25

CN8–> Vestibular Nuclei–> Thalamus–> Via thalamocortical (bilateral) pathway–> Cortex

Question 26

What is tested in the Tracking Test?

Answer 26

The vestibulo-ocular reflex

Question 27

What is nystagmus?

Answer 27

The slow movement of eyes as they are catching up to movement of the head

Question 28

What types of nystagmus are indicative of vestibular disease?

Answer 28

Resting nystagmus and

Positional nystagmus

Question 29

What is Estropia?

Answer 29

Crossed eyes- physiological nystagmus

Siamese and Himalayan cats

Question 30

A unilateral lesion causes resting nystagmus. The fast phase of the vestibulo-ocular reflex goes towards the _____ side.

Answer 30

intact side

Question 31

The fast phase of the vestibulo-ocular reflex goes away from the _______ side.

Answer 31

lesioned

Question 32

What kind of nystagmus is seen in an animal with a peripheral vestibular lesion?

Answer 32

Horizontal or Rotatory Nystagmus ONLY

Does NOT change when head moves, not positional

Question 33

What kind of nystagmus is seen in an animal with a central vestibular lesion?

Answer 33

Horizontal, Rotatory or Vertical Nystagmus

MAY CHANGE when animal is in recumbancy, may be positional

Question 34

What does the Vestibulocollic Reflex do?

Answer 34

Produces neck movements and forelimb extension to counteract head tilt

Question 35

What is a unilateral lesion?

Answer 35

When one side fires and one side does not, or is impaired

Question 36

What happens to the vestibulocollic reflex when there is a unilateral lesion?

Answer 36

Controlled by cerebellum

Head tilts towards LESIONED side

Question 37

What is the Vestibulospinal reflex responsible for?

Answer 37

Controlled by cerebellum

To prevent falling when head moves by producing limb extension

Question 38

If there is a unilateral lesion, what happens to the vestibulospinal reflex?

Answer 38

The animal will lean or circle toward the side of the lesion

Question 39

What problem is associated with the Emetic Center?

Answer 39

Motion sickness