pt 2: sensory input ch 2: echolocation in bats bat behavior decoding the acoustic environment
Sensory and Motor Mechanisms pt. 3
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Transcript of Sensory and Motor Mechanisms pt. 3
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• Twitches tetanus (smooth, sustained contraction)
– Connected via tendons and connective tissues
Motor units in a vertebrate skeletal muscle
REVIEW!!!• Know these for the AP:• Know the neuron • Neurons with myelin
sheath white 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
KNOW THIS TOO!