Neuromuscular Basis of Action

Neuromuscular Basis of Action - Neuromuscular Basis of...

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Neuromuscular Basis of Action The Motor Unit Central Nervous System (CNS) consists of the brain and the spinal cord. o spinal nerves are attached to the spinal cord by a ventral (motor) root - from anterior horn dorsal (sensory) root - from posterior horn o these join to form a spinal nerve then split into: anterior - trunk and limbs posterior - back and branches o each branch contains motor and sensory nerves these terminate in neurons each terminal branch of a neuron ends at a structure called the motor end plate. here the signal is transmitted across a gap (the synapse) by neurotransmitter (acetyl choline) this results in an action potential being created in the postsynaptic membrane of the muscle fiber A motor unit is a single motor neuron plus all the muscle fibers that neuron supplies from 10 fibers to 2000 fibers contracts in an "all-or-none" fashion, if the stimulus is above a threshold value, ie, either all the fibers contract, or none of them contract X A muscle with a high motor unit to muscle fiber ratio (meaning few fibers per motor
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This note was uploaded on 09/25/2010 for the course EXS 31757 taught by Professor Brennan during the Spring '10 term at Oakland University.

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Neuromuscular Basis of Action - Neuromuscular Basis of...

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