The Motor System 1

Question 1

What are the forms of activity?

Answer 1

Motor function
Sensory function
Sensory-motor integration
Cognition

Question 2

What does the motor system involve mainly?

Answer 2

Movement within the body/ of parts of the body in space

Question 3

What are the individual movements?

Answer 3

Limb
Trunk
Neck
Facial
Eye
Tongue and throat

Question 4

Describe the hierarchical plan of the motor system

Answer 4

UMN
LMN
NMJ
Muscle

Question 5

Describe an upper motor neurone

Answer 5

Cell body in the brain

Control Lower motor neurons

Question 6

Describe a lower motor neurone

Answer 6

Cell body in motor nuclei of brainstem (if controlling head and neck- cranial nerves) or spinal cord in the anterior horn (CNS)
Control muscles

Question 7

What are the types of muscles/ where they are in the body?

Answer 7

Limb
Truncal
Bulbar- face and head

Question 8

How do we control muscle movement?

Answer 8

Organise the muscles into agonist and antagonist muscles

Question 9

What type of organisation does muscles working in groups reflect?

Answer 9

Neural

Question 10

What does a LMN typically control?

Answer 10

A focal anatomically adjacent group of muscle fibres

Question 11

How does UMN and LMN differ in action on muscles in terms of organisation?

Answer 11

UMN= groups of muscles
LMN= individual muscles movements

Question 12

What are the functional motor components of muscles?

Answer 12

Muscle fibres

Question 13

Where do the lower motor neurone axons terminate?

Answer 13

In the muscles to control the muscles

Question 14

What do motor end-plates (myoneural junctions) consist of?

Answer 14

Motor nerve fibre ending and the subjacent part of the muscle fibre

Question 15

What is the neurotransmitter used in NMJ?

Answer 15

ACh

Question 16

Which motor neuron cords from the spinal cord control which body parts?

Answer 16

Cervical cord= arms
Thoracic cord= trunk
Lumbosacral cord= legs

Question 17

How are bulbar muscles supplied?

Answer 17

Cell bodies in brain stem nuclei axons travel in cranial nerves to supply bulbar muscles

Question 18

How do axons of spinal cord LMNs pass out?

Answer 18

Nerve roots and periphery nerves

Question 19

What is the gross anatomy of the peripheral nerve?

Answer 19

Motor neuron and sensory neuron, nerve fibre (axons), endoneurium (connective tissue around the myelin sheath of each myelinated nerve fiber) in nerve trunk

Question 20

What is the motor unit?

Answer 20

A motor neurone and the muscle fibres supplied by that neurone
Number of muscle fibres in a motor unit varies from 1-100s depending on the need for precision in movement

Question 21

How are limb muscles supplied?

Answer 21

Cell bodies in spinal cord grey matter axons travel in roots/ periphery nerves

Question 22

How are truncal muscles supplied?

Answer 22

Cell bodies in spinal cord grey matter axons travel in roots/ thoracic nerves

Question 23

What are the causes of systemic muscle disease?

Answer 23

Genetic
Metabolic
Autoimmune

Question 24

What does weakness tend to be?

Answer 24

Generalised
Symmetrical
Proximal

Question 25

Where may LMN disease be?

Answer 25

Spinal cord
Spinal root and nerves
Brain stem
Cranial nerves

Question 26

What are the most clinically important nerve roots?

Answer 26

Upper limb= C5, 6, 7
Lower limb= L5
Degenerative disease, disc prolapse common

Question 27

What are the clinically important motor nerves in the upper limb?

Answer 27

Median
Ulnar
Radial

Question 28

What are the clinically important motor nerves in the lower limb?

Answer 28

Sciatic
Common peroneal (around fibula head)

Question 29

What is polyneuropathy?

Answer 29

All of the axons in peripheral nerves are affected