Spinal tracts/ Muscle fibres Flashcards

1
Q

what type of info do ascending pathways carry?

A

sensory

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2
Q

how many orders does the ascending pathway have

A

4

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3
Q

what does DCML carry

A

fine touch, vibration, proprioception

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4
Q

what r the two parts of the DCML and what do they relate sensory info for

A

fasciculus cuneate- upper limb

fasciculus gracilis- lower limb

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5
Q

what r the two parts of the spinothalamic tract and what type of sensory information do they carry

A
anterior= crude touch and pressure
lateral= pain and temp
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6
Q

what does spinocerebellar carry

A

unconscious proprioceptive information from muscle to cerebellum

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7
Q

what type of info do descending pathways carry?

A

motor

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8
Q

how many orders of neurons does the descending pathway have

A

2

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9
Q

what r the 2 classification of descending tracts

A

pyramidal and extrapyramidal

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10
Q

what do pyramidal tracts carry

A

voluntary control of muscle

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11
Q

what do extrapyramidal tracts carry

A

involuntary/ autonomic control of musculature

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12
Q

what re the two pyramidal tracts and what do they carry

A

corticospinal- results of body muscles

corticobulbar- head and neck muscles

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13
Q

what r the 4 extrapyramidal tracts

A

vestibulospinal
reticulospinal
rubrospinal
tectospinal

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14
Q

what is the path fo the DCML

A
  1. respective fasciculus bring info up to reach the dorsal root ganglia and ascend ipsilaterally
  2. decussate at medulla
  3. ascends to contralateral thalamus to go to contralateral somatosensory cortex
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15
Q

what is the path fo the spinothalamic

A
  1. reaches dorsal root ganglion from receptors in periphery
  2. decussation 1/2 levels above ventral horn
  3. ascends to contralateral thalamus to go to contralateral somatosensory cortex
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16
Q

what does vestibulospinal tract carry and where does it come from

A

balance and posture

vestibular (8th) nucleus

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17
Q

what does reticulospinal tract carry and where does it originate from

A

muscle tone and voluntary movement

pons

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18
Q

what does tectospinal tract carry and where does it originate from

A

movment of head in relation to vision

superior colliculus

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19
Q

what does rubrospinal tract carry and where does it originate from

A

fine control of hand movement

red nucleus

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20
Q

what r the 2 extrapyramidal tracts that decussate

A

rubrospinal and tectospinal

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21
Q

path of corticospinal tract

A
  1. ascends though corona radiata to the internal capsule
  2. 85% decussates at medulla and goes contralateral and 15% remains ipsilateral
  3. terminates at the ventrolateral horn of the spinal cord and synapses onto 2 order neurons
22
Q

path of corticobulbar tract

A
  1. corona radiata to internal capsule to crus cerebri, pons and medulla
  2. synapse at cranial nerve nuclei to supply head and neck muscles
23
Q

5 stages of neurotransmitter cycle at NM junction

A
  1. manufacture
  2. storage
  3. release
  4. interaction (NT with post synaptic receptors)
  5. inactivation (of NT)
24
Q

compare bells palsy to stroke (UMN/LMN, what order neurone, where is teh lesion)

A
bells= LMN affected, 2nd order neurones, CN 7 lesion
stroke= UMN affected, 1st order neuorons, UMN lesion
25
Q

what is a motor unit

A

alpha motor neurone and the extrafusal skeletal muscle it innervates

26
Q

function of alpha motor neurons

A

voluntary muscle contraction

27
Q

function of gamma motor neurons

A

controls muscle contraction in response to external forces acting on muscles

28
Q

what does a smaller motor unit mean

A

fine regulation/ control

29
Q

what muscle is controlled by lateral and medial alpha motor neurones

A

lateral- distal muscle

medial- proximal

30
Q

what r the two things intrafusal muscles fibres sense and for what reason

A

sense stretch and monitors muscle length and rate of change to prevent overstretching of muscles

31
Q

types of intrafusal muscle fibres and functions (2)

A

1a- excites alpha motor neurones

2- inhibits alpha motor neurones

32
Q

what do golgi tendons detect and what type of sensory fibres do they have and what is its function

A

tension
1B
if too much tension, golgi tendon inhibits muscle from contracting

33
Q

what is a muscle spindle made of and what does it detect

A

intrafusal fibres and stretch receptors

stretch

34
Q

efferent and afferent supply of muscle spindle

A
efferent= gamma
afferent= 1a (fast), 2 (slow)
35
Q

types of pain and what tract carries them and what fibres is this

A

slow pain- anterior spinothalamic C fibres

fast pain- lateral spinothalamic alpha fibres

36
Q

what is the neurotransmitter for fast acting pain, where does it act and what fibre is this

A

glutamate
at 1st and 2nd order neurones
alpha fibres

37
Q

what is the neurotransmitter for slow acting pain and what fibre is this

A

glutamate AND substance p

C fibres

38
Q

what does substance p do and how

A

gives nociception (dull achy pain) by binding for longer

39
Q

analgesic vs anaesthetics

A

analgesic- selective pain suppression, consciousness not affected
anaesthetics- total pain suppression, consciousness can be affected

40
Q

ascending pathway for PAIN

A
  1. nociceptors sense pain
  2. trasnmit impulse to DRG via alpha or c fibres
  3. decussation 1-2 spinal levels above where alpha becomes lateral and c fibres become anterior
  4. go to thalamus to the somatosensory cortex
41
Q

compare alpha and c fibres

A
alpha= unmyelinated
c= myelinated
42
Q

what is pain gate and what is the effect of this

A

small descending pathways that inhibit interneurones of the spinothalamic tract
prevent impulses reaching the somatosensory cortex

43
Q

which 3 tracts decussate at the medulla

A

DCML
corticobulbar
corticospinal

44
Q

what is end plate potential adn how is the AP propagated

A

like at a NM junction but stronger depolorisation

propagated to all adjacent fibres in an alpha motor unit

45
Q

compare UMN and LMN lesion location

A
UMN= between motor cortex and the spinal cord
LMN= between spinal cord and muscle
46
Q

compare UMN and LMN lesion damage symtoms

A
UMN= hypertonia, spasticity (hyperactive kid)
LMN= hypotonia, muscle atrophy (slow grandad)
47
Q

what is conus medularis and what level does this occur

A

where the spinal cord becomes tapered

L1/2

48
Q

what is cauda equina

A

nerves from lumbar and sacral nerves handing obliquely downwards

49
Q

what is the filum terminale and what does it contain

A

fibrous strand extending from conus medullaris to coccyx

50
Q

curves of the vertebral column name and direction

A

cervical and lumbar curve anterior

thoracic and sacral curve posterior