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Sensory and Motor Mechanisms pt. 3. Neural Control of Muscle Tension. 2 mechanisms graded contractions of whole muscles varying the number of fibers that contract Recruitment of motor units to activate varying the rate at which fibers are stimulated
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Neural Control of Muscle Tension • 2 mechanisms graded contractions of whole muscles • varying the number of fibers that contract • Recruitment of motor units to activate • varying the rate at which fibers are stimulated • Twitches tetanus (smooth, sustained contraction) • Connected via tendons and connective tissues
REVIEW!!! • Know these for the AP: • Know the neuron • Neurons with myelin sheathwhite matter. • Neurons without myelin sheath gray matter. • Myelin sheath speeds up the transmission white matter is faster than gray matter • Electrical impulses are sent down the axon
REVIEW! (cont’d) • The neuron’s resting potential is -70mV • Na+ rushes back… fires Action potential • A neuron cannot fire during the absolute refractory period • In order for an impulse to be fired it much reach the threshold (-55 mV) • Depolarization- Na+ Channels open • Repolarization- K+ Channels open • Calcium: • Too little Ca+ spasms • Too much Ca+ neuron is hard to fire