山东大学：《医学生理学 Medical Physiology》课程教学资源（PPT课件讲稿，人体生理学 Human Physiology）Chapter 10 Nervous System part 4 Motor Functions of the Nervous System

Part 4 Motor Functions of the Nervous system I Motor Unit and final common pathway

Part 4 Motor Functions of the Nervous System I Motor Unit and Final Common Pathway

Ventra root Ventral Lower he orn Mixed motor spinal Muscle neurons nerve fib er

1. Motor unit

1. Motor Unit

Alpha motor neuron every striated muscle has encapsulated Gamma moto muscle fibers neuron scattered throughout the muscle called muscle spindles Extrafusal muscle fibers Extrafusal and muscle fibers intrafusal fibers

•Every striated muscle has encapsulated muscle fibers scattered throughout the muscle called muscle spindles. •Extrafusal and intrafusal fibers

Alpha motor neuron The extrafusal muscle fibers are innervated by alpha motor Gamma motor neuron neuron The intrafusal muscle fibers are innervated by gamma motor Extrafusal neurons muscle fibers Intrafusal muscle fibers

The extrafusal muscle fibers are innervated by Alpha motor neuron The intrafusal muscle fibers are innervated by Gamma motor neurons