KINE 3P94 Lecture Notes - Lecture 4: Intrafusal Muscle Fiber, Neural Coding, Afferent Nerve Fiber
29 Feb 2016
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Pekn 3p94 lecture 4: monday, september 30, 13. Henneman"s size principle (small large motor units recruited/derecruited: advantages: Small movements produce small amounts of force, therefore not generating more force than required. Movements that require lots of force production very quickly. Cant selectively activate the larger motor units, must go through small ones first. Rate coding: increases force beyond 50-85% mvc. Numerous factors need to be considered in order for muscle to generate the desired amount of force. Sensory info drives motor output: must have sensory receptors afferent transmission (dorsal route) spinal cord (interneurons) motor neuron (afferent transmission) effector organ. Lie parallel with the extrafusal muscle fibers (form the bulk of your muscle) Muscle spindles are within the intrafusal fibers. Stretching in intrafusal fibers causes change in firing rate. When the muscle is shortened we see a silent period (no firing) When the muscle returns to resting length it returns back to initial firing rate: secondary afferent:
