Lecture 7.2: Descending Pathways Flashcards

1
Q

What are the 3 Types of Movement?

A

1) Reflexes
2) Posture
3) Voluntary Movement

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2
Q

What type of movement do LMNs & Spinal Cord Circuits facilitate?

A

Reflexes

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3
Q

What type of movement do the Brain Stem & Spinal Cord facilitate?

A

Posture

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4
Q

What type of movement do the Cortex, Brain Stem & Spinal Cord facilitate?

A

Voluntary Movement

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5
Q

What Structures is the Motor Cortex comprised of? (2)

A
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6
Q

What is the Primary Motor Cortex?

A
  • Encodes the Direction of Movement
  • Somatopically Organised
  • Motor Homunculus
  • Head Laterally
  • Feet Medially
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7
Q

What is the Role of the Corticospinal Tract?

A

Conscious control of skeletal muscles

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8
Q

What 3 tracts does the Corticospinal Tract split into? (3)

A
  • Corticobulbar
  • Lateral Corticospinal
  • Anterior Corticospinal
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9
Q

What is the Corticobulbar part of the Corticospinal Tract responsible for?

A

Conscious control over eye and face muscles

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10
Q

What is the Lateral Corticospinal part of the Corticospinal Tract responsible for?

A

Conscious control over limb skeletal muscles

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11
Q

What is the Anterior Corticospinal part of the Corticospinal Tract responsible for?

A

Conscious control over axial skeletal muscles

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12
Q

What does the Corticospinal Tract descend via?

A
  • Pyramids of the medulla
  • 75-90% decussate – mainly distal musculature
  • 10-25% don’t decussate – axial
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13
Q

What is the Origin of the Corticospinal Tract?

A

Primary Motor Cortex

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14
Q

What does the Corticospinal tract synapse onto?

A

The Ventral Horn

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15
Q

What are the 4 Brain Stem Motor Pathways (Extrapyramidal)?

A
  • Rubrospinal Tract
  • Tectospinal Tract
  • Vestibulospinal Tract
  • Reticulospinal Tract
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16
Q

What is the Role of the Rubrospinal Tract?

A
  • Voluntary control of upper limb motor activity
  • Lesions produce minimal effects, demonstrating
    overlap
17
Q

What is the Role of the Tectospinal Tract? (2)

A
  • Orientation and positioning of the head for balance * Eye-head coordination
18
Q

What is the Role of the Vestibulospinal Tract? (2)

A
  • Head Balance
  • Body Posture
  • Involuntary
19
Q

What is the Role of the Reticulospinal Tract? (2)

A
  • Body Posture
  • Muscle Tone
20
Q

Where does the Rubrospinal Tract originate from?

A

Originates in the red nuclei of the brain stem

21
Q

Is there full unilateral facial drooping in Bell’s Palsy or a Supranuclear Lesion of the Facial Nerve?

A

Bell’s Palsy

22
Q

What is Motor Neurone Disease?

A

Degeneration of the motor cortex, spinal tracts, anterior horn grey matter & LMNs

23
Q

What are the Clinical Features of Motor Neurone Disease? (5)

A
  • Stiffness/weakness of the hands spreading distal to
    proximal
  • Fasciculations
  • Speech Difficulties
  • Swallowing Difficulties
  • Slow, Progressive Muscle Wasting – distal to
    proximal
24
Q

What are Fasciculations?

A

Visible, involuntary twitching of an individual muscle

25
Q

What is Myasthenia Gravis?

A
  • Disorder of the NMJs
  • Autoimmune disease w Abs against acetylcholine
    receptors
26
Q

Clinical Features of Myasthenia Gravis

A
  • Variable Muscle Weakness
  • Fatiguability
27
Q

Diagnostic Tests for Myasthenia Gravis (3)

A
  • Antibodies
  • EMG
  • Edrophonium Test
28
Q

Treatment of Myasthenia Gravis (2)

A
  • Cholinesterase Inhibitors (symptomatic)
  • Immunosuppression/Thymus Removal