Spinal Cord Flashcards

1
Q

What is the function of the Corticospinal tract

A

conveys axial and limb motor control

controls voluntary movement of muscle

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2
Q

Describe the corticospinal tract

A

Begins in the precentral gyrus (primary motor cortex)
>internal capsule>cerebral peduncle>pons>pyramids>Lateral/Anterior Corticospinal tract
80% decussate in pyramids

  • *80% decussate at pyramids so they just synapse with neuron on anterior horn (limb)- Lateral corticospinal tract
  • *20% decussate same side on anterior white commissure then synapse in anterior horn of grey matter -Anterior corticospinal tract

any lesion here is UMN lesion

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3
Q

What are the 2 neurons involved in the Corticospinal tract

A
  1. Upper motor neuron (from cerebral cortex to ventral horn)

2. Lower motor neuron
from ventral horn to skeletal muscle

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4
Q

Describe the
Reticulospinal tract
-function
pathway

A

Posture and locomotion

  • form reticular formation(pons) to spinal cord
  • regulates ventral horn motor activity/reflexes
  • facilitates and inhibits lower motor neurons
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5
Q

Amyotrophic lateral sclerosis

A
  • Genetic (SOD1 gene)
  • Affects LMN and UMN selectively
  • progressive weakness and atrophy of muscles but mind intact
  • spasticity when UMN affected
  • symptoms usually in limbs or bulbar signs
  • short life span due to resp failure
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6
Q

Spinocerebellar tract

  • function
  • pathway
A
ipsilateral, 2 neurons
unconscious muscle proprioception 
Posterior Tract: above L3
1st order- synapse at dorsal horn
2nd order- ascend in lateral column to cerebellum (terminate ipsilaterally in cerebellar cortex after entering through inferior cerebellar peduncle)
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7
Q

Spinothalamic Tract

A
First Order Neurons 
-enter dorsal horn 
-form tract of Lissauer 
-Synapse in substantia gelatinosa 
2nd Order Neurons 
- cross in dorsal horn at each level 
-ascend in anterolateral column to thalamus
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8
Q

how does UMN lesion occur?

-cause?

A

damage to corticospinal tract

e.g following a stroke

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9
Q

UMN disease

-symptoms

A
  • Spastic paralysis (increased muscle tone)
  • Overactive tendon reflexes
  • No significant muscle atrophy

Above pyramids: Opposite side
Below pyramids: Same side

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10
Q

how can a LMN lesion occur?

A

Degeneration of lower motor neurons in ventral horn
E.g. Spinal muscular atrophy
- caused by defects in the SMN1 gene

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11
Q

LMN disease

-symptoms

A
  • Flaccid paralysis (no muscle tone)
  • No tendon reflexes
  • Muscle atrophy
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