Motor units
- Created by: cara12
- Created on: 15-04-19 10:44
View mindmap
- Motor units
- A motor neuron plus all the muscle fibres it innervates
- To carry out impulses from the central nervous system to the muscle fibres to initiate muscular contraction
- Summarising role of motor unit
- 1.Nerve impulse initiated in the motor neuron cell body
- 2.Nerve impulse conducted down the axon of the motor neuron by a nerve action potential to the synaptic cleft
- 3.Neurotransmitter called acetylcholine is secreted into the synaptic cleft to conduct the nerve impulse across the gap
- 4.If the electrical charge is above threshold,the muscle fibre will contract
- 5.'All or none law' fashion
- Axon carries the electrical impulse from the cell body to neuromuscular junction.
- Neuromuscular Junction-The point where motor neuron communicates with muscle fibre across a space called the synapse
- Synapse-The space between a motor neuron and skeletal muscle
- Motor end plate-The area of muscle fibre that establishes synaptic contact with motor neurone
- 1.Resting potential-The neuron at rest.There is lower charge inside the neuron than outside
- 2.Action potential-The electrical activity carried down the axon.
- 3.Neurotransmitter-Chemical messenger that transmits across synapse and binds to muscle fibres to initiate contraction
- 4.Acetylcholine-The neurotransmitter released at neuromuscular junction that travels across synapse
- 5.All or none law-If the action potential threshold is reached,all muscle fibres in the motor unit are activated.
- If it is not reached,no muscle fibres are activated.
- A motor neuron plus all the muscle fibres it innervates
Comments
No comments have yet been made