NRSC 335 Final: Exam 4 (FINAL)

• School: Texas A&M University
• Department: Neuroscience
• Course: NRSC 335
• Professor: Stephen Maren

Document Summary

Actions defined by skeleton (range/direction) and muscles (force/rate) Made of muscle fibers that have filamentous proteins (actin and myosin) Fast fiber - quick movements (sprint); slow fiber - sustained movements (posture, marathon) Nmj - large efficient synapse; uses ach! Ach receptors on muscle fiber mediate depolarizing na+ current. Muscle ap release ca+ from intracellular stores to initiate actin/myosin. Proprioception: muscle (6th) sense; info to the brain. Location of limbs, state of muscle contraction, activity of motor centers. 2 types of sensory organs: muscle spindles and golgi tendon organs. Golgi tendon organ responds to stretch and contraction. Load on spindle -> muscle stretches -> excite spindle. Pyramidal (direct projection) - motor to spinal motoneurons. Cortical neurons fire to guide mvmt direction. Electrode stimulation in cortex produces fine movements (not mere muscle activity) Motor cortex has topographic map of muscles. Supplementary motor cortex (mii) - when to act. Posterior parietal cortex - what can be done.