NM - 10

Question 1

What is a motor unit and the difference between large and small motor units

Answer 1

Consists of a motor neuron and all of the muscle fibres it innervates

Motor units a that are large are greater than 100 muscle fibres eg postural muscles

Small are less than 10 fibres eg muscles requiring precise control

Question 2

Ways you can increase muscle contraction (2)

Answer 2

By activating more motor unite ie recruitment
By Activating motor units more ie by increasing stimulus frequency to cause summation or tetanus

Question 3

What is electromyography

Answer 3

Measures the electrical activity of skeletal muscle by placing electrodes in or near the muscle

Question 4

Why would a clinician order an EMG

Answer 4

If a patient has signs or symptoms that may indicate a nerve or muscle disorder

Question 5

What are slow muscles

Answer 5

Adapted for slow sustained , tonic and fatigue resistant contractions eg postural muscles

Question 6

What are fast muscles

Answer 6

Adapted for rapid intense, phasic and easily fatigued contractions eg gastrocnemius

Question 7

How are muscles characterised

Answer 7

Based on speed of contraction and ATP production

Question 8

What is Type I

Answer 8

Slow oxidative

Question 9

What IIa

Answer 9

Fast oxidative

Question 10

what is type IIb

Answer 10

Fast - glycolytic

Question 11

What’s does fast mean

Answer 11

higher Myosin ATPase activity

Question 12

What does oxidative

Answer 12

ATP produced by oxidative phosphorylation
Much more efficient than glycolysis – more resistant to fatigue

Question 13

what does glycolytic

Answer 13

generate ATP via anaerobic glycolysis (White Fibres) – Inefficient method which also produces lactic acid

Question 14

What training do to muscle fibres

Answer 14

Improve oxidative capacity (more resistant to fatigue) * Increase blood supply/number of mitochondria
– Change muscle fibre diameter
* Size of muscle increased (hypertrophy) by short, high intensity,
anaerobic exercise (e.g. weight lifting) * Affects fast-glycolytic fibres

Question 15

what is deneravtion

Answer 15

A lesion of the motor nerves to skeletal muscle

Question 16

What is fasciculations

Answer 16

Visible twitching caused by release of Ach from degenerating motoneurons

Question 17

Type I and II ATROPHY

Answer 17

occurs in peripheral neuropathies, disuse (bedrest, spaceflight, immobilization), myasthenia gravis etc.

Mainly type II atrophy with Duchenne muscular dystrophy and ageing

Question 18

What is Type II hypertrophy

Answer 18

Occurs with weight training

Question 19

Neuromuscular disease is due to … (3)

Answer 19

Neuropathy
Junctionopathy
Myopathy

Question 20

what is neuropathy

Answer 20

disease affecting nerves) in the central or peripheral nervous system or both (peripheral nerves, e.g. motor neuron disease; multiple sclerosis etc.)

Question 21

What is junctionopathy

Answer 21

(Neuromuscular junctions, e.g. myasthenia gravis)

Question 22

What is myopathy

Answer 22

(disease affecting muscle, e.g. muscular dystrophies)