SSEH1101 Study Guide - Final Guide: Alpha Motor Neuron, Motor Unit, Muscle Tone
19 Jun 2018
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SSEH1101: Revision Notes 6
Motor Unit Contraction:
1. Motor unit!
2. Recruitment!
3. Muscle tone!
Motor Unit:
-It includes a motor (effector) neuron!
-AND the muscle fibres that the effector neurons innervate!
Recruitment:
-Either small motor units or large motor units!
-Small motor units recruited when: needed for precise movements!
-Large motor units recruited when: needed for gross movements!
Muscle Tone:
-Asynchronous motor unit contraction causes?!
-CONSTANT state of LOW-LEVEL tension on the muscle!
Whole muscle contraction:
1. Frequency of stimulation!
2. Number of motor units recruited!
3. Degree of stretch of the muscle!
Frequency of stimulation:
-can be single stimulus !
-Can be multiple stimuli!
Multiple Stimuli: SEE GRAPH IN LECTURE NOTES!
-Treppe!
-Temporal summation!
-Incomplete tetanus!
-Complete tetanus!
-Fatigue!
Number of Motor Units Recruited:
-Stimulation voltage changes to recruit motor units by INCREASING its voltage!
-Types of stimulus:!
-Sub threshold stimulus!
-Treshold stimulus!
-Recruitment!
-Maximal stimulus!
Degree of Muscle Stretch:
-Can be un-stretched muscle!
-Moderately stretched muscle!
-Overstretched muscle (risk of injury here)!
Document Summary
Motor unit contraction: motor unit, recruitment, muscle tone. And the muscle bres that the e ector neurons innervate. Either small motor units or large motor units. Small motor units recruited when: needed for precise movements. Large motor units recruited when: needed for gross movements. Constant state of low-level tension on the muscle. Whole muscle contraction: frequency of stimulation, number of motor units recruited, degree of stretch of the muscle. Stimulation voltage changes to recruit motor units by increasing its voltage. Muscle bre is basic structural unit of muscle. When it is stimulated = contracts to fullest extend. Muscle bre does not act as independent unit. + muscle bres that alpha motor (e ector) neuron innervates. Factors a ecting force production: temporal summation, motor unit recruitment, length of muscle. Affected by the firing rate of alpha motor neuron. Firing rate a ects action potential, a ection stimulus to motor unit.
