PHGY 209 Lecture Notes - Alpha Motor Neuron, Intrafusal Muscle Fiber, Golgi Tendon Organ
Document Summary
Motor behavior: purposeful or goal directed, two types, voluntary movements, reflexive: more important component. Thousands of little small muscle contractions in body, trunk that keep us sitting up. We would flop over if this whole motor component would be turned off. By inhibiting the motor neurons that innervate that muscle: during flexion, the opposite happens. The flexor muscle becomes the agonist and contracts while the extensor muscle becomes the antagonist and relaxes: to keep things at a constant position, we have to balance the forces on either side of the joint. Reciprocal innervation of muscles: coordinated flexor and extensor muscle activation and relaxation, both of these things go off every time we move, limb position is maintained by a balance of flexor and extensor muscle tension. Motor neurons (-> neuromuscular junction: only excitatory (ach) is released at the neuromuscular junction, motor neurons only cause muscles to contract since that would involve inhibiting the motor neuron that is innervating it.
