LECTURE 8: ascending and decending pathways Flashcards

1
Q

what kind of pathways are ascending pathways

A

sensory pathways

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2
Q

what is the function of the somatosensation

A

need to distinguish between sensory information from sensation

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3
Q

what interprets sensation giving us perception as active process between us and environment

A

thalamus and cortex

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4
Q

what neurons are ones with long axons that carry info long ways

A

projection neurons

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5
Q

_ neurons pathways include ___ projection neurons that may also have ____

A

3 and 3 and interneurons

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6
Q

what does the 1st order neuron do

A

bring into from periphery to CNS ( SC or BS)

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7
Q

what neuron bring in for from SC or brainstem to thalamus

A

2nd neuron

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8
Q

what does the 3rd neuron do

A

thalamus to somatosensory cortex

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9
Q

what are teh 3 types of somatosensory pathways to the brain

A

conscious relay
divergent
non conscious relay

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10
Q

what pathways is detailed and discriminative sensation are conveyed

A

conscious

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11
Q

what pathway is in for transmitted to may location in the brainstem and cerebrum with different #’s of neurons

A

divergent

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12
Q

how many projection neurons do conscious replay pathways have

A

3

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13
Q

what is the conscious relay pathway responsible for

A

light touch, proprio , noncicpetion , temp

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14
Q

what are the 2 ways the conscious relay pathways travel up. the SC to the brain

A

dorsal columns an anterolateral columns

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15
Q

what is the dorsal columns responsible for

A

conscious proprioception , light touch

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16
Q

what is the anterolateral columns responsible for

A

pain and temp

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17
Q

where does crude awareness have to go

A

to the thalamus

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18
Q

for detailed awareness where does sensory information has to go

A

somatosensory cortex and be processed there

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19
Q

what is stereognosis

A

being able to identify an object with tactile manipulation with eyes closed

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20
Q

where is the 1st order neurons for the dorsal column medial lemnicus pathways

A

dorsal root ganglion and then enter gray matter of dorsal horn

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21
Q

where is the second order neuron in the DCML

A

medulla and then goes up to the thalamus

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22
Q

where does the axons cross in DCLM

A

2nd order neuron in the medulla , cross at the midline as internal accurate fibers and then ascen to DCLM pathway

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23
Q

when does the 1st synapse happen in the DCML

A

in the nucleus gracilis or cuneatus depending where it is coming from

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24
Q

where is the 3rd order neuron in the DCML

A

in thamlus and then going to the pormary somatosensory cortex ( post central gyrus)

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25
Q

what is the secondary somatosensory gyrus

A

immediately post to primary , processes info from primary somatosensory gyrus and thalamus from sterognosis and sensory

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26
Q

what is the anterolateral pathways responsible for

A

crude touch , pain , temp

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27
Q

what pathways does the anterolateral pathways have

A

conscious and divergent

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28
Q

what is the lateral spinothalamic tract responsible for

A

fast nociception and temp

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29
Q

what is the anterior spinothalamic tract responsible for

A

crude tube

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30
Q

what do C fibers transmit

A

crude touch

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31
Q

what do A- delta and C fibers transmits

A

temp

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32
Q

what fo A- delta fibers with free nerve ending transmit

A

fast nociception ( mechanical)

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33
Q

where does the lateral spinothalamic tract cross at

A

anterior commissure in the SC

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34
Q

where does the 3rd order neuron go in teh lateral spinothalamic tract

A

synapses in the thalamus and goes thru the internal capsule and goes to primary and secondary association of somatosensory cortices

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35
Q

slow nociception that reach conscious awareness go thru what

A

spino emotional pathway

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36
Q

what are the 1st order neurons for slow - medial nociception ( c fibers)

A

c fibers with free nerve endings that synapse in the dorsal horn

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37
Q

what are the 2nd order neurons of the slow - medial nociception

A

projection neurons ascend to reach midbrain , reticular formation (pons) and emotion areas thru sc in 3 tracts

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38
Q

what are the 3 tracts that the 2nd order neurons go thru for slow - medial nociception

A

spinomesencephalic
spinoreticular
spino-emotional

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39
Q

what is the spiniomescencephalic

A

it is the superior colloculus and periaqueductal gray matter in the midbrain

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40
Q

what is the spinoreticualr

A

reticular formation

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41
Q

what is the spino - emotional

A

thalamus then going to anterior cingulate gyrus , insula , amygdala, dorsolateral prefrontal cortex

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42
Q

wher does subconscious temperature transmit to

A

reticular formation , thalamus l subcortical nuclei , and hypothalamus

43
Q

what are spinocerebellar tracts

A

non conscious relay tracts that are very important for unconscious postural and movement adjustments

44
Q

where does the posterior/ dorsal spinocerebellar tract come from and does it cross

A

form LE and lower body and doesn’t cross

45
Q

where is the 1st order neuron for the posterior spinocerebellar

A

cell body at the dorsal root ganglion and then synapses at the clark’s nucleus in the dorsal gray matter

46
Q

where is the 2nd order neuron posteior spinocerebellar tract

A

forms the post. spinocerebellar tract within the fasciculus gracilis and then goes thru the inferior cerebellar peduncle to cerebellar cortex

47
Q

so if there is a problem in the right side of the cerebellum what side of the ebody will be affected

A

right side

48
Q

where does the cuneocerebellar comes form

A

face , neck , UEs, and upper body

49
Q

in the cuneocerebellar tract where does the 1st and 2nd order neuron synapse

A

lateral cuneate nucleus in medulla and then enters thru inferior cerebellar peduncle

50
Q

what are examples of the internal feedback tract

A

anterior spinocerebellar and rostrospinocerebellar tract

51
Q

what is the path for the anterior spinocerebellar tract

A

cell bolts in the spinal throacolumbar gray matter in ventral horns and then axons cross the midline of the SC and ascend to the midbrain and then fibers go thru the superior peduncles and most of them cross a 2nd time to go to the cerebellum while other stay contractleral

52
Q

during the anterior spinocerebellar tract each cerebellar hemisphere receives input from

A

B sides of body

53
Q

where do the internal feedback tract start

A

inside of the spinal cord

54
Q

what is the path for rostrospinocerebellar tract

A

get info from cervical sc and T1 to ipsilateral cerebellum thru inferior and superior cerebellar peduncles

55
Q

when we use sensory information to anticipate needs for movement we use

A

feedforward mechanisms

56
Q

when we use sensory information during or after the movement we are using

A

feedback mechanisms

57
Q

is the gray matter or white matter filled with cell bodies

A

gray

58
Q

what cells are the primary output cells in the cerebrum

A

pyramidal cells

59
Q

what is the white matter filled with

A

axons

60
Q

what fibers extend from the sub cortical to cerebral cortex or from cortex to SC brainstem , basal ganglia ,and thalamus

A

projection fibers

61
Q

what connects homologous areas of hemispheres

A

comissural fibers

62
Q

what fibers connect cortical regions within 1 hemispheres can be long or short

A

association fibers

63
Q

what are the internal capsule do

A

project fibers either to the brian or from the brain to the sc

64
Q

where do descending motor tracts originate form

A

in the cerebral cortex ( pyramidal) or brainstem (extrapyramidal)

65
Q

where do descending motor tracts descend to

A

descend to down to synapse with alpha or gamma MNs and/or interneurons in the brainstem or SC

66
Q

what adjusts the motor tract activity of the descending motor tracts

A

cerebellum and motor aspects of basal ganglia

67
Q

where do postural/gross movement synapse at in the motor tract

A

mediakky

68
Q

where do fine movement synapse at in the motor tract

A

laterally

69
Q

what are the 2 pyramidal tracts

A

corticospinal and corticobulbar tract

70
Q

what is the function of the lateral corticospinal tract

A

voluntary limb and fractionates movement

71
Q

what is the function for the medial corticospinal tract

A

automatic trunk and proximal movements

72
Q

what is the function for the corticobulbar tract

A

face

73
Q

the pyramidal tracts come from where

A

the primary motor cortex and premotor cortex

74
Q

whar are the 2 extrapyramidal tracts

A

reticuolospinal and vestibulospinal tract

75
Q

what does the reticulospinal tract facilitate

A

postural and gross llimb movements , coordinates trunk and prox muscles of 4 limbs of walking and anticipatory postural changes for reaching

76
Q

there are abnormal synergies post BI due to ______ writhing adjustments from ____

A

reticulospinal tract

77
Q

what is the function of the medial vestibulospinal tract

A

takes informatiom about head movement and position form vestibular apparatus and affects activity of neck and upper back

78
Q

what is the function of the lateral vestibulospinal tracts

A

info about gravity from vestibular apparatus facilitating MNs to extensors when head is upright

79
Q

what is the path for the reticulospinal tract and vestibulospinal tract

A

Originate in the BS and then comes down to the ventral horn of their tract and and then leave

80
Q

in the corticospinal tract what is the flexor - extensor rule for LMNs in the SC

A

MNs that innervate flexor mm are located more posteriorly to MNs that innervate extensors

talking about thru the tract on the SC

81
Q

in the corticospinal tract what is the proximal - distal rule for LMNs in the SC

A

MNs that inn distal mm are located lateral to MNs that innervate proximal mm

talking about the tract on the SC

82
Q

where does the lateral corticospinal tract cross

A

decussates at pyramidal decussation of medulla

83
Q

where does the medial CST cross

A

it doesn’t cross

84
Q

where does the lateral CST originate from

A

primary motor cortex

85
Q

where does the medial CST originate from

A

promoter cortex

86
Q

where does the lateral CST descends thru

A

laterla funiculus of sc

87
Q

where does the medial CST descend thru

A

medial / ventral funicuclus of SC ( anterior white matter)

88
Q

what is the difference between the pathway for the lateral and medial CST

A

the lateral CST comes from the primary motor cortex and the medial CST comes from the promotor cortex they both travel down but the lateral crosses at the pyramidial decussation at the medulla and the medial CST does not cross and the lateral CST descends in the lateral funiculus of SC and the medial CST descends in medial funiculus of SC and they both synapses on interneurons or Mns in ventral horn

89
Q

what do nonspecific motor tracts facilitate

A

activity of interneurons and MNs in SC

90
Q

when are nonspecific motor tracts active

A

during intense emotions

91
Q

what are examples of the nonspecific motor tracts

A

ceruleospinal tract and raphespinal tract

92
Q

where does the ceruleopspinal tract originate and release

A

originates from locus coeruleus at junction between midbrain and pons and releases norepinephrine for tonic facilitation of spinal MNs

93
Q

where does the raphespinal tract originate and release

A

originates from raphe nuclei of upper medulla and release serotonin to modulate spinal MNs

94
Q

what does the corticobrainstem tracts provide

A

voluntary control of many mm of head and head

95
Q

what is the path of the corticobrainstem tracts

A

originate in the cerebral cortex’s motor areas and reach CN nuclei in brainstem to activate MNs that innervate mm of face , tongue , pharynx , larynx and traps and scm

96
Q

where is the primary motor cortex

A

precentral gyrus

97
Q

where is the premotor cortex

A

immediately anterior to primary motor cortex , lateral surface

98
Q

what is the function of the premotor cortex

A

prepares for movement esp those that invovled serval joints

99
Q

where is the supplementary motor cortex

A

immediately anterior to primary motor cortex, superior and medial surface

100
Q

what is the function of the supplementary motor cortex

A

replanning movements

101
Q

what are signs or motor tract lesions

A

paresis
abnormal reflexes
myoplasticity
abnormal muscle tone e
loss of fractioned mvmt
abnormal cocontraction

102
Q

what kind of fibers is the corpus callosum and anterior commisure

A

commissural fibers

103
Q

cingulum , short associayion fibers , superior longitudinal fasciculus and inferior longitudinal fasciculus are exmaples of what type of fibers

A

association fibers

104
Q

what is an example of projection fibers

A

internal capsule