Lecture 7 - Neuromuscular Aspects of Movement II

Question 1

what is the CNS?

Answer 1

• the central nervous system
• the brain
• the spinal cord

Question 2

what is the PNS?

Answer 2

• the peripheral nervous system
• nerve branch pairs (12 cranial and 31 spinal)
• plexuses (cervical, brachial, lumbar and sacral)

Question 3

where are nerve branch pairs located?

Answer 3

• between each pair of spinal vertebrae

Question 4

where are plexuses located?

Answer 4

• after leaving the spinal column, branches are formed

Question 5

what are the two types of nerves?

Answer 5

• afferent and efferent

Question 6

what are afferent nerves?

Answer 6

• aka sensory nerves
• to brain
• sensory

Question 7

what are efferent nerves?

Answer 7

• aka motor nerves
• leaving brain
• motor
• control movements of the muscles

Question 8

what is a myotome?

Answer 8

• the area of muscle controlled by a specific nerve pair
• differ slightly between people

Question 9

what is a dermatome?

Answer 9

• the area of the body ‘felt’ by a specific nerve pair
• differ slightly between people

Question 10

what is the motor cortex?

Answer 10

• the part of the brain that decides which muscles to activate
• where commands come from when you want to move yourself

Question 11

what is the somatosensory cortex?

Answer 11

• next to the motor cortex
• where feelings from the body parts arrive for processing

Question 12

what is the ‘motor homunculus’?

Answer 12

• the parts of the body controlled by the motor cortex
• the larger the area, the greater and finer the control
• hand and mouth are predominant

Question 13

what is a motor unit?

Answer 13

• all the muscle fibres activated by one motor nerve
• for fine control, would have ~10 fibres
• for powerful muscles, would have ~1000 fibres

Question 14

what is an EMG?

Answer 14

• electromyography
• measures the signal in the motor nerve as an action potential is fired
• can be measured with a surface EMG or fine wire EMG (inserted via needle)

Question 15

why would we use surface EMG?

Answer 15

• to measure the muscle tone (sound of muscles)
• measure many muscles simultaneously to record the sequencing of muscle activation

Question 16

why would we use fine wire EMG?

Answer 16

• measures only one or two fibres
• more specific

Question 17

what are the 3 muscle fibre types?

Answer 17

1. type I
2. type IIa
3. type IIb

Question 18

what are type I muscle fibres?

Answer 18

• slow twitch
• oxidative
• fatigue resistant
• slow to contract
• marathon muscles

Question 19

what are type IIa muscle fibres?

Answer 19

• fast twitch
• oxidative
• fast to contract
• fatigue resistant
• create lactic acid

Question 20

what are type IIb muscle fibres?

Answer 20

• fast twitch
• glycolytic
• fast to contract
• fast to fatigue (glycolysis)
• no oxidative phosphorylation
• sprint muscles

Question 21

what is elastic storage of energy?

Answer 21

• the energy stored in muscles (tendons) following stretch
• it is released when the muscle shortens

Question 22

what is the stretch-shorten cycle?

Answer 22

• the bend you do before full extending (like trying to jump as high as you can)
• causes a build-up of elastic energy

Question 23

what is the length-tension curve?

Answer 23

• addition of all sarcomeres to make muscle curve, plus add the elasticity of the perimysium

Question 24

what is muscle power?

Answer 24

• power = force x velocity

Question 25

what is proprioception?

Answer 25

• 6th sense
• ability to know what position our joints are in without looking
• afferent nerves take signals from the muscles and send it to the brain to supply us with movement sense

Question 26

what types of sensors are responsible for proprioception?

Answer 26

• golgi tendon organs in tendons
• spindle fibers in muscles
• pressure sensors in joints
• cutaneous sensors in the skin

Question 27

how can you improve proprioceptive feedback?

Answer 27

• taping (KT tape)
• increases skin feeling, does not support biomechanical loading