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Flashcards in week 11 Deck (64)
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1
Q

vestibular system maintains

A

head and body posture maintained in relation to head

2
Q

vestibular disease is an ____ disease

A

assymetric

3
Q

what can cause vestibular disease

A

inner ear on one side
CN VIII on one side
medulla lesion that gets one vestibular trigone, but not the other

4
Q

what is the classic sign of vestibular disease

A

head tilt

5
Q

head tilt is on what side

A

the side of the least vestibular tone (usually the side of the lesion)

6
Q

what are the receptros for the vestibular system

A

crista ampullaris

macula

7
Q

crista ampullaris

A

dendritic zone of CN VIII (vestibular part), tonically active, on/off
adjusts body posture in relation to head movement to maintain balance

8
Q

macula

A

dendritic zone of CN VIII; primarily affected by gravity

detects static head position and linear acceleration/deceleration

9
Q

cranial nerve VIII

A

receptors, axonz, vestibular ganglion, axons, into medulla, vestibular nuclei

10
Q

important projections from the vestibular nuclei

A

vestibulospinal tract
medial longitudinal fasciculus
projection to cerebellum

11
Q

what are the signs of vestibular disease

A
head tilt
rolling, falling, circling
vestibular ataxia
abnormal nystagmus
ventrolateral strabismus (transient)
12
Q

normal nystagmus

A

same sized pupils
eyes centrally located in orbit
eye should not be moving

13
Q

spontaneous nystagmus

A

loss of tonic stimulation of CN II, IV, VI

14
Q

Vertrical

A

central!

15
Q

pendulous

A

no fast or slow phase
oscillatory movements back and forth
typically not vestibular (genetic in siamese)

16
Q

positional nystagmus

A

elevate head, turn head to side, or twist head
if nystagmus ensues-> positional
vertical -> central
changes position -> central

17
Q

peripheral disease

A
lesion in PNS
CN VIII or Inner ear
head tilt towards side of lesion
asymmetric ataxia
horizontal or rotary nystagmus (fast phase away from side of lesion); more commonly acutely
eye drop on side of lesion
18
Q

3 keys to peripheral

A

classic vestibular signs
no loss of strength
postural responses

19
Q

bilateral peripheral disease

A

no head tllt; no vestibular nystagmus

20
Q

central disease

A

lesion in CNS (medulla)
classic vestibular signs
spastic hemiparesis/paresis (UMN)
proprioceptive ataxia (GP below trigone)
postural response deficits (UMN and GP)
Vertical nystagmus
nystagmus with fast phase towards head tilt
nystagmus that changes directions when you move head
change in mentation
also could see LMN signs of CNN V, VI, VII, IX, X, XII

21
Q

Horner’s syndrome

A

sympathetic neuron cell bodies to eye (T1, T2, T3); cranial cervical ganlgion to middle ear; CN VII, VIII

22
Q

Moving head to right turns off

A

left

23
Q

if still and looking to right

A

left turned on

24
Q

central lesion in cerebellum that affects the vestibular nerve occurs where

A

flocculonodular lobe or more commonly, the caudal peduncle

25
Q

caudal peduncle carries

A

inhibitory purkinje fibers from flocculonodular lobe to vestibular nuclei

26
Q

in paradoxical vestibular disease, you have increased vestibular tone on what side

A

on side of lesion (due to loss of inhibition); appears as though unaffected side has decreased vestibular tone

27
Q

therefore, head tilt, rolling, falling, circling on what side

A

unaffected side

28
Q

can see hemiparesis on

A

opposite side

29
Q

out of the 18 UMN, how many descend into the spinal cord

A

8

30
Q

most UMN synapse on

A

interneurons

31
Q

UMN fibers are ______ size

A

medium

32
Q

larger diamter neurons are more prone to

A

compression

33
Q

what size motor neurons have faster transmission

A

larger

34
Q

pyramidal system includes

A

UMN that travel through pyramids

35
Q

lateral corticospinal tract

A

important in primates for voluntary movement; 100% crossover; not important in domestic animals for movement

36
Q

forebrain disease in domestic species

A

have fairly normal gait but postural responses will NOT be normal due to pyramidal system

37
Q

forebrain signs include

A
behavior changes
seizures
visual loss wit intact PLR
normal gait
but, postural response deficits
38
Q

damage and clinical deficits with a brain lesion

A

opposite side affected

39
Q

damge to cord lesion

A

same side affected

40
Q

postural responses

A

the entire nervous system must be working properly for them to work

41
Q

extrapyramidal system cell bodies located in

A

brainstem (3 midbrain, 1 pons, 3 medulla)

42
Q

extrapyramidal system under control of

A

frontal cortex and basal nuclei

43
Q

extrapyramidal system important in domestic animals

A

initiates voluntary movement

initiate and maintain normal posture

44
Q

rubrospinal tract located in

A

mesencephalon

45
Q

rubrospinal tract starts in

A

red nucleus (very vascular; red)

46
Q

rubrospinal tract important in domestic animals because

A

excitatory to LMNs of flexors

47
Q

if damaged, rubrospinal tract

A

difficult initiating voluntary movement
profound gait deficits
UMN signs likely
postural response deficits

48
Q

tectospinal tract located in

A

mesencephalon

49
Q

tectospinal tract begins at

A

tectum

50
Q

function of tectospinal tract

A

excitatory to LMNS of flexors primarily in neck (rostral and caudal colliculi for sight and sounds avoidance)

51
Q

tectotegmentospinal tract located in

A

mesencephalon

52
Q

tectotegmentospinal tract originates from

A

tectum and tegmentum (2 locations for cell bodies)

53
Q

sympathetic control of the eye

A

umn center for GVE nerve fibers destined to go to the head; pupillary dilation (LMNs T1-T3)

54
Q

pupillary dilation

A

turn off parasympathetic
turn on sympathetic
preganglionic parasympathetic in midbrain, post ganlgionic in ciliary ganglion

55
Q

where can damage occur to cause damage to sympahtetic innervation

A

spinal cord cranial to cell bodies (UMN)
C6-T2)
VAGOSYPATHETIC TRUNK
MIDDLE EAR INFECTION

56
Q

what are the clinical signs of horner’s syndrome

A
miosis (constricted pupil)
enophthalmis
3rd eyelid protrusion
ptosis
sweating in horses due to increased blood flow
*signs can have degree of severity*
57
Q

pontine reticulospinal tract begins in the

A

pons

58
Q

pontine reticulospinal tract function

A

excitatory to extensors

59
Q

medullary reticulospinal tract begins in

A

medulla

60
Q

medullary reticulospinal tract inhibitory to

A

LMNs of extensors

61
Q

together, medullary reticoluospinal and pontine reticulospinal control

A

rest of GVE LMNs in cord; primarly urination/defecation

62
Q

medial longitudinal fasciculus is in the

A

myelencephalon

63
Q

medial longitudinal fasciculus is UMN tract for

A

CN 3, 4, 6

64
Q

Medial longitudinal fasciculus also runs caudally in

A

ventral funiculus of cord