PHGY 209 Lecture Notes - Lecture 10: Extrafusal Muscle Fiber, Intrafusal Muscle Fiber, Golgi Tendon Organ

• School: McGill University
• Department: Physiology
• Course: PHGY 209
• Professor: Ann Wechsler

Document Summary

Motor behavior: purposeful or goal directed; two types, voluntary and reflexive, agonist is muscle contracting and antagonist is muscle relaxing, flexion, flexor muscle contracts (agonist) and extension, extensor muscle contracts (agonist) Reciprocal innervation of muscles: coordinated flexor and extensor muscle activation and relaxation, limb position is maintained by a balance of flexor & extensor muscle tension. Interneurons integrate information from tendon, skin, joint receptor, descending pathway, and muscle receptor (+ or -: and synapses on motor neuron, tendon monitors tension, while muscle receptor monitor muscle length, descending pathway for voluntary control from the brain. Irradiation: magnitude of withdrawal reflex depends on the magnitude of the pain stimulus: due to recruitment of more interneurons in spinal cord, afterdischarge: response maintained after stimulus termination, due to spinal feedback loops. It is resistance to re-extend, don"t want to extend back. Muscle spindle and golgi tendon organ: golgi tendon organ: monitor muscle tension.