spinal cord part 2 Flashcards

1
Q

how many circuits are in the spinal cord?

A

2

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2
Q
  • contained all within one segment

- come in and go out the same segment

A

myotactic reflexes

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3
Q

circuits that cross into or through many different spinal cord segments

A

intersegmental or multisegmental

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4
Q
  • responsible for coordination events
  • central pattern generator
  • breathing, walking
  • rhythmic activity
A

ascending multisegmental circuits

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5
Q
  • wiring that connects the different segments of the CNS
  • they bring sensory info to the conscious
  • three separate ascending pathways into brain
A

multisegmental circuits

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6
Q
  • afferent but getting sensory info from muscles
  • uses clarkes columns and external cuneate nusclei in spinal cord
  • part of spinocerebellar pathways
A

proprioception

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7
Q
  • conscious experience
  • dorsal column nuclei shuttles the info
  • dorsal column nuclei give rise to the dorsal columns at the base of the brain which is also called the lemniscus system
A

touch pressure

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8
Q
  • clarkes columns
  • external cuneate nucleus
  • spinocerebular
  • ipsi
A

proprioception

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9
Q
  • dorsal column
  • cross at base/brain stem
  • contra
  • VPLN
A

touch pressure

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10
Q
  • sub gelatinous
  • nucleus proprius
  • cross spinal cord
  • VPLN
  • contra
A

pain/temp

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11
Q
  • conscious experience
  • info carried by spinothalamic tract
  • uses the subtantia gelatinous and the nucleus proprius at the spinal cord
A

pain and temperature

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12
Q
  • most go down through clarke’s column and the external cuneate nucleus
A

descending multisegmental tracts

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13
Q
  • largest tract in primates
  • 2/3 of neurons start at motor cortex
  • mediates voluntary movement
  • starts as large cells in all parts of the cortex, mostly broddmans 4
A

corticospinal tract

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14
Q

what is the corticospinal tract also called

A

pyramid tract

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15
Q

what are the two divisions of the pyramid tract (corticospinal tract)?

A

lateral corticospinal and anterior corticospinal tracts

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16
Q
  • motor commend for muscle control
  • 90% of fibers
  • cross at medulla (decussation)
  • cell bodies in motor cortex ( layer V )
  • limb muscles
A

lateral corticospinal tract

17
Q
  • 10% of fibers
  • cell bodies in the motor cortex (layer V)
  • runs ipsi and then branch at the spinal segment
  • proximal trunk muscles
A

anterior corticospinal tract

18
Q

why do a lot of neurons go to sensory areas as well as motor areas when they descend?

A

to modulate the ascending input

19
Q

what is a common pattern of all sensory systems?

A

rostral sites of projection in the sensory systems always send descending feedback

20
Q

what kind of feedback does the rostral site send?

A

inhibitory

21
Q

why is it important for the brain to comodulate?

A

the brain coordinates the type of input it gets

22
Q
  • cell body in cortex
  • dont go out of periphery
  • not a “motor” neuron because it does not innervate a muscle
  • part of corticospinal and corticobulbar
A

UMN (upper motor neuron)

23
Q
  • cell body in spinal cord or cranial nerve cell body in brainstem
  • axons innervate muscles in periphery
A

LMN (lower motor neuron)

24
Q

damage to the pyramidal tract causes….

A
  • hyperflexion and problems with fine motor control
25
Q

what does damage to the pyramidal tract cause hyperflexion?

A

the inhibitory effects of a normal working descending corticospinal tract are used to tone down reflexes

26
Q

what is a sign that damage to the pyramidal tract has caused oversensitivity of the reflexes?

A

babinski sign

27
Q

how does damage to the corticospinal tract cause CP (cerebral palsy)

A

the cortex is damaged, but still in tact and working, but you dont see the inhibition from the corticospinals and therefore you get hyperflexion

28
Q

what are disorders of UMN

A
  • increased tone
  • spacticy
  • over reactive tendon reflex (babinski)
  • can not quickly contract muscles
  • affects groups of muscles
29
Q

disorders of LMN

A
  • results in muscle atrophy
  • fibrillation
  • loss of reflex
  • decreased tone
  • affects single muscles
30
Q
  • starts in the red nucleus
  • cross at midline in the midbrain and then runs down the length of the spinal cord next to the corticospinal tract
  • it terminated at both sensory and motor fibers about 1/2 and 1/2
A

rubrospinal tract

31
Q
  • receives input from the cerebellum and the cortex
  • in midbrain
  • could be apart of reticular formation
A

red nucleus

32
Q

this tract

  • is involved in the excitation of the flexors and inhibition of the extensors
  • the flexors and extensors are innervated by different neurons
  • if there werent different neurons there wouldnt be movement
A

rubrospinal tract

33
Q
  • begins at the level of the reticular formation (pons, medulla, parts of midbrain)
  • its a sampling mechanism
  • receives info from the cerebrum and the cerebellum
  • allows the reticular formation to influence muscles
  • both excitatory and inhibitory
A

reticulospinal tract

34
Q

what is a sampling mechanism

A

samples info going up and down the brain stem and prioritizes

35
Q
  • slows vestibular input to be translated back down to the motor neurons
  • allows muscles in trunk, limbs, and head to adjust to balance info
  • starts at vestibular nuclei in medulla
  • ipsi only system
  • no sensory connections, requires no feedback
A

vestibulospinal tract

36
Q

where does the vestibular nuclei get the info from?

A

cranial nerve VIII and cerebellum

37
Q
  • starts at superior colliculus
  • sends input to the cervical region of spinal cord from lower brain stem
  • its purpose is to work in head tuns to visual stimuli and tracking behaviors
A

tectospinal tract

38
Q
  • located midline in the brain stem
  • inhibitory to the spinal cord and to sensory areas
  • part of the reticular formation
  • its main function is in pain control
A

raphe nucleus