Properties Of The Motor Unit

Question 0

Define motor neurone pool

Answer 0

Collection of motor Neurones that innervated a single muscle

Question 1

Define the motor unit

Answer 1

Lower motor neurone and the muscle fibre it innervates

Question 2

Define alpha motor neurone

Answer 2

Directly trigger generation of force by muscle

Question 3

Why is the cervical region enlarged?

Answer 3

Innervate 50 muscles of Upper Limbs

Question 4

Why is the Lumbar region enlarged?

Answer 4

Innervate muscles of the Lower Limbs

Question 5

How many motor neurones innervate a muscle fibre

Answer 5

1

Question 6

How many muscle fibres can a single motor neurone innervate

Answer 6

Many

Question 7

In the sliding filament hypothesis, contraction and relaxation are______

Answer 7

Active processes

Question 8

Describe the sequence of contraction

Answer 8

Ca2+ bind to troponin causing conformational change 
Myosin binding site exposed 
Myosin head binds to actin 
Myosin disengage and uncock using ATP
Repeat

Question 9

How do you increase the force of contraction

Answer 9

Increase firing of alpha motor neurones
Recruit additional synergistic motor units
Change structure of muscle fibre - increase number of cross bridges, increase force/velocity of cross bridge

Question 10

What are the inputs to spinal motor neurones

Answer 10

Spinal Interneurons
Muscle Spindles
Upper motor neurones in brain

Question 11

What are muscle spindles

Answer 11

Specialised muscle fibres (type 1a sensory axons) within fibrous capsule

Question 12

What is a myotactic reflex

Answer 12

Monosynaptic
From Sensory fibre to alpha motor neurone
Patella Reflex