PSY290H1 Study Guide - Comprehensive Final Guide: Homeostasis, Testicular Atrophy, Inferior Colliculus
Document Summary
Comparing the two dorsolateral motor pathways and the two ventromedial motor. Pathways: both have axon tracts descending into spinal cord and brain stem to spinal cord, they differ: Axons here terminate directly innervate interneurons on both sides of spinal gray matter. Motor neurons project to distal muscles proximal muscles: originate in cerebral cortex, voluntary movement, however different functions as shown in monkey studies. Motor units are smallest unit of motor activity (comprises of a single motor neuron and all of the individual skeletal muscle fibers) Motor neuron fires, all muscle fibers contract. A motor unit with fewest muscle fibers (fingers) permits highest degree of selective motor control. Skeletal muscles have many muscle fibers bound together and attached to bone via tendon. Acetylcholine is released by motor neurons at neuromuscular junctions and activates the motor end-plate causing fiber to contract. Muscles only generate force in one direction. All muscle neurons innervating fibers of a muscle motor pool.
