Physiology - Spinal disorders Flashcards Preview

MBBS - Year 1 > Physiology - Spinal disorders > Flashcards

Flashcards in Physiology - Spinal disorders Deck (29)
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1
Q

Upper motor neurone pathology

A

Spasticity – pt’s will have stiff muscles w/ brisk tendon reflexes
Normal peripheral nerves

2
Q

Where do lower motor neurones start

A

Start at anterior horn cell body

3
Q

Lower motor neurone pathology

A

Flaccid paralysis, lost tone and power

Loss of axons or peripheral nerve cell body

4
Q

Sensory function nerves

A

Discriminative touch

Pain and temperature

5
Q

Discriminative touch

A

Ability to distinguish objects, shapes, surfaces, textures with skin. Provided by large, myelinated nerve fibres

6
Q

Pain and temperature - sensory nerves

A

Provided by small, unmyelinated nerve fibres

7
Q

What does the effect of denervation depend on

A

Where the damage is

8
Q

The most common effects of denervation are

A

Loss of function in root distribution

Loss of function in distribution of named nerve

9
Q

Pathology of peripheral nerves resulting in denervation

A

Pathology of myelin, if severe enough will lead to secondary axon damage
Pathology of axons
Infl of blood vessels e.g. vasculitis can also damage axons

10
Q

Epineurium

A

Membrane surrounding nerve

11
Q

Perinuerium

A

Membrane surrounding fascicle

12
Q

Things that can go wrong leading to axon damage

A

Damage to myelin – acquired or inherited

Direct injury to axons from toxins or metabolic disturbance or secondary axonal damage due to demyelination

13
Q

Causes of damage to axons - trauma

A

Compression e.g., carpal tunnel syndrome or ivd prolapse
Transection e.g., knife wound
Stretching

14
Q

Causes of damage to axons - disease (peripheral neuropathy)

A
Diabetes, B12 deficiency 
Infl, autoimmune 
Infection, HIV, Leprosy 
Drugs and toxins 
Inherited
15
Q

Length dependent peripheral neuropathy

A

Loss of function affects most distal parts of body first

16
Q

Non-length dependent peripheral neuropathy

A

Loss of function occurs in patches and can affect short and long nerves

17
Q

Radiculopathy

A

Damage of nerve root

18
Q

Types of axon loss

A

Axonotmesis
Neurotmesis

Recovery of both requires axon regrowth - 1mm/day

19
Q

Axonotmesis

A

Damage of few axons, can recover but slow and may be incomplete

20
Q

Nuerotmesis

A

Complete transection of nerves, recovery requires grafting transected ends

21
Q

Neuropraxia

A

damage to nerve in the form of myelin, temporary and reversible

22
Q

Recovery of myelin damage

A

8-12 weeks after removal of cause

23
Q

Wallerian degeneration

A

When an axon has been cut, calpain gets released which is activated and breaks down components of nerve over 3 days before macrophages move in and clear debris.

24
Q

Reinervation after Wallerian degeneration

A

The ends of the axon still attached to the cell body will start to regenerate

25
Q

Effects of denervation on sensory nerves

A

Altered sensation

Numbness
Pain due to loss of axons supplying discriminative touch
Paresthesia - axons that are hyperexcitable

26
Q

Effects of denervation of motor nerves

A

Atrophy
Weakness
Paralysis

27
Q

Effects of denervation in muscles

A

Begin to waste – atrophy

Begin to generate spontaneous motor activity

28
Q

Spontaneous motor activity as a result of denervation

A

Fibrillations and fasciculations

Cramps

29
Q

Muscles viability without nerve supply

A

Up to 2 yrs

After which they fibrose and can’t return to normal function

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