Motor Units Flashcards Preview

DC A Level PE - Anatomy & Physiology > Motor Units > Flashcards

Flashcards in Motor Units Deck (8)
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1
Q

What is a motor unit?

A

A nerve cell and all of the muscle fibres that the nerve cell is in contact with that it controls (innervates)

2
Q

What is a motor neuron?

A

A nerve cell in the brain or spinal chord that transmits nerve impulses (electrical signals) to a group of muscle fibres via a motor end plate

3
Q

What is an axon?

A

An extension of a motor neuron that connects the main nerve cell to the muscle fibre

4
Q

What is the neuromuscular junction?

A

The point where the axons motor end plates meet the muscle fibre

5
Q

What is the synaptic cleft?

A

A gap between the motor end plate and the muscle fibre

6
Q

What determines the strength of the contraction?

A

The number of motor units that are recruited (more = greater strength)

7
Q

What is muscle action potential?

A

+ve electrical charge inside the nerves and muscle cells which conduct the nerve impulse down the motor neuron and into the muscle fibres

8
Q

What is the ‘all or none’ law

A

Either all of the muscle fibres in the motor unit will contract or none will (if the charge is high enough)