PHGY 209 Lecture 32: Motor System
Document Summary
Interneuron -> a nerve cell found entirely within the central nervous system that acts as a link between sensory neurons and motor neurons. Information sent from brain to perform a goal, has a purpose. Two types of motor behavior: voluntary, reflexive -> out of control & awareness. Flexion: the flexor muscle contracts while the extension muscle relaxes, the angle around the joint decreases. Reciprocal innervation of muscles means activating both muscles: both are coordinated in activation and relaxation, balance between the muscles tensions. Spinal reflexes: withdrawal reflexes -> protects limbs from injury, stretch reflex -> controls muscle length, inverse stretch reflex -> controls muscle tension. Most spinal reflexes can be overridden: withdrawal reflexes, flexion withdrawal reflex: Polysynaptic (goes through 2 synapses before reaching motor neuron, interneurons between sensory input and motor output): This is before the brain knows it. Experience pain and usually the withdrawal reflex occurs.
