KINESIOL 2Y03 Lecture Notes - Lecture 11: Motor Neuron, Motor Unit, Quadriceps Femoris Muscle
29 Nov 2017
School
Department
Course
Professor
Document Summary
You can only stimulate a muscle to contract. Somatic motor neuron cell body in spinal cord, exits via ventral root. Neuron splits at perimysium and serves many muscle fibers. A single motor neuron and the fibers it serves - is called a motor unit. Each motor unit serves fibers of the same type. To make a force on our muscle more stronger. Recruit more motor units, more fibers involved, more force. The more motor units you recruit, greater tension on muscle. Number of fibers in the muscle has not changed. They have larger muscle fibers (building more contractile proteins) Length of muscle does not change, but tension increases. You"re not moving but your muscle is contracting. The force is greater than what you"re able to do. Tension produced is constant, but length of muscle changes. Concentric - myosin pulls actin towards m line, shorter sarcomere. Eccentric - muscle lengthens, when resistance greater than tension.
