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Revision Notes - Year 1 > Spinal cord compression - 129 > Flashcards

Spinal cord compression - 129 Flashcards

1
Q

Where do afferent neurons conduct to/from?

A

Conduct signals from sensory receptors INTO the CNS

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2
Q

Where do efferent neurons conducts to/from?

A

Conduct motor/effector signals from the CNS OUT to effectors, e.g. muscle

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3
Q

What is a ganglion?

A

A collection of neurons usually located outside the brain

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4
Q

What are the 5 components to each reflex circuit? (Regarding spinal reflexes)

A

1) sensory receptor 2) afferent path to CNS 3) synapse within CNS 4) efferent path from CNS 5) effector

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5
Q

What do inhibitory interneurons in the spinal cord allow for?

A

Contraction of agonist and simultaneous relaxation of the antagonist

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6
Q

Which root does sensory information pass through?

A

Dorsal root

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7
Q

Efferent information passes through which root in the spinal cord?

A

Ventral

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8
Q

What do muscle spindles do?

A

Detect changes in muscle length, stretch generates an action potential.

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9
Q

What is a myotatic reflex? What is the function of this reflex?

A

Stretch reflex.
Muscle lengthens -> muscle spindle is stretched and its nerve activity increases. Increases alpha motor neuron activity -> muscle fibers contract and resist stretching.
A secondary set of neurons causes opposing muscle to relax.
The reflex functions to maintain the muscle at a constant length.

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10
Q

What does tetanus toxin do?

A

Inhibit glycine release

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11
Q

What is responsible for making you drop heavy things? Why does this happen?

A

Golgi tendon organ. Has a higher threshold than muscle spindle and is activated by prolonged stretch, Ib afferent. Activation produces inhibition of homonymous muscle, preventing tendon damage

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12
Q

Do alpha motor neurones cause muscle contraction or spindle contraction?

A

Muscle contraction. The spindle is flaccid.

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13
Q

What causes muscle spindle contraction? What is the purpose of this?

A

Gamma motor neurons. It regenerates tension in the muscle

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14
Q

What cells are involved in recurrent inhibition?

A

Renshaw cells.

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15
Q

What are Renshaw cells?

A

inhibitory interneurones found in gray matter of spinal cord -> associated with an alpha motor neurone. They are excited by a-motor neurone, release glycine back onto the motor neurone, thus inhibiting firing. This allows synergistic muscles to contract together.

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16
Q

Where does descending motor control originate?

A

Pyramidal cells of motor cortex

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17
Q

What is apraxia?

A

Inability to produce a specific motor act even though sensory and motor pathways are intact - e.g. cannot execute a movement on request.

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18
Q

Name 2 descending tracts

A

Corticobulbar and corticospinal

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19
Q

What is the anterolateral system?

A

Ascending pathway that comprises 3 main pathways

20
Q

What are the 3 main pathways of the anterolateral system?

A

Spinothalamic, spinoreticular and spinotectal

21
Q

What are some classic signs and symptoms of a LMN lesion?

A

Hyporeflexia, fasiculations, muscle atrophy, denervation.

22
Q

What are some classic signs and symptoms of an UMN lesion?

A

Paralysis, hyperreflexia, increased muscle tone, spasticity, babinski relex, bladder, bowel and sexual dysfunction

23
Q

Where do corticospinal fibres most commonly decussate?

A

At the junction of the medulla and spinal cord

24
Q

Where do fibres of the spinothalamic tract most commonly decussate?

A

In ventral white commissure. Pain and temperature axons usually cross within 1 segment of origin. Touch and pressure may ascend several segments before crossing.

25
Q

What is Brown-sequard syndrome?

A

Any presentation of spinal injury that is an incomplete lesion (hemisection)

26
Q

A hemisection of the spinal cord will result in a loss of touch, pain, temperature and pressure where?

A

On the opposite/contralateral side of the lesion.

27
Q

What is cauda equina syndrome?

A

Compression of lumbar and sacral nerve roots within the cauda equina

28
Q

How might a patient with cauda equina syndrome present?

A

Red flags are: urinary retention, faecal incontinence, saddle anesthesia, pain on straight leg raise, weakness of ankle plantar and dorsi flexion

29
Q

What is complex about a patient with amytrophic lateral sclerosis when regarding signs/ symptoms?

A

They will have a mixture of UMN and LMN signs/symptoms. It is a motor neurone disease

30
Q

How might a patient with ALS present?

A

Dysarthria, slow tongue movements, brisk jaw jerk, weakness, wasting, fasiculations

31
Q

What is motor neurone disease?

A

Disease causing wasting of the anterior horn cells with resulting upper and lower mostor neuron symptoms

32
Q

What cells are lost in motor neurone disease?

A

Anterior horn cells

33
Q

How might you treat motor neurone disease?

A

Palliatively, there is no effective treatment. Riluzole can increase life expectancy by 3 months

34
Q

What is myasthenia gravis?

A

An acquired autoimmue disease with antibodies against nicotinic ACh receptors at the neuromuscular junction.

35
Q

What are the main symptoms someone with myasthenia gravis will suffer from?

A

Muscle weakness and fatigue

36
Q

Which muscles are more affected in Myasthenia gravis? (Proximal or distal)

A

Proximal

37
Q

What other condition/abnormality is myasthenia gravis often associated with?

A

Thymus abnormalities.

38
Q

What investigations would be done if you expected a patient to have myasthenia gravis?

A

Serology -> ACh and Muscarinic antibodies. Neurophysiology, Edrophonium test (a reversible aceytlcholineesterase inhibitor)
Could also do the peek test

39
Q

How would myasthenia gravis be treated?

A

ACh esterase inhibitors, immunosuppressive drugs, Ab treatment, ?surgery

40
Q

Where would a transection of the spinal cord need to be to cause quadraplegia?

A

At the cervical regions

41
Q

Paraplegia is a result of a transection of what area of the spinal cord?

A

Below cervical regions

42
Q

What is the term for weakness in 1 limb?

A

Monoparesis

43
Q

Radiculo- pertains to what?

A

nerve root

44
Q

How would you describe paralysis of both legs?

A

Paraplegia

45
Q

Hemiplegia describes what?

A

Paralysis of 1 side

46
Q

Quadraparesis describes what?

A

Weakness of 4 limbs

Revision Notes - Year 1 (41 decks)

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