ANPS 019 Lecture Notes - Lecture 18: Skeletal Muscle, Motor Unit, Inverse Relation
17 Oct 2018
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Document Summary
Motor neurons transmit signals from cns to the muscles they innervate. The motor nerve axons branch and individually innervate numerous skeletal muscle fibers. A single motor neuron + the fibers it controls = a motor neuron. Small motor neurons = less than five muscle fibers. Inverse relationship between size of motor unit and degree of control. Muscle tension is the force exerted by a contracting skeletal muscle on an object. The opposing force exerted by the object is called the load. Muscles do not always shorten during contraction. Muscle tension is easily measured in the laboratory. The muscle twitch is a muscle fibers response to a single electrical stimulation. Provides a way to study how molecular events influence muscular activity. Muscles responses are graded allowing for fluid and appropriate movement. We dont move by making a series of muscle twitches. An important characteristic of skeletal muscle is the ability to contract to varying degrees- graded responses.
