KNES 385 Lecture 17: Proprioception and motor units
26 Oct 2016
School
Department
Course
Professor
Document Summary
The alpha motor neurons innervate the extrafusal muscle fibers that are responsible for generating force: extrafusal muscle fibers get contracted. Extrafusal muscle classic muscles that are spoken about (they contract) The gamma motor neurons innervate the intrafusal muscle fibers in muscle spindles: not contracting the muscle, intrafusal muscle fibers. Every muscle fiber is innervated by exactly one motor neuron. One motor neuron can innervate many muscle fibers. Innervation ratio: the number of muscle fibers innervated by a motor neuron: motor neurons can activate many fibers or motor neurons that can activate a very small number of fibers. Walking doesn"t need to many specific motor neurons. Fine movements might need more motor neurons. Motor pool: all the motor neurons that innervate a particular muscle. The cell bodies of all the motor neurons in a motor pool are clustered together in the spinal cord.
