01:377:370 Lecture Notes - Lecture 1: Alpha Motor Neuron, Afferent Nerve Fiber, Neuromuscular Junction
29 Feb 2016
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Document Summary
Action potential- nerve conducts a signal na channels open once threshold is reached and na rushes into cell. Refractory period- time after ap when another ap cannot be generated (retrograde motion) Suprathreshold stimulus- repeated stimulus gives multiple ap in given time period. Central ns (cns)- brain and spinal cord. Peripheral ns (pns)- nerves that transmit information to and from cns: afferent division (sensory)- take information to cns, efferent division (motor)- take information away from cns to periphery. Autonomic ns (ans)- involuntarily activates smooth and cardiac muscle, sweat and salivary glands, some endocrine glands. Sympathetic ns- fight or flight response activating heart, smooth muscle, sweat glands, viscera. Parasympathetic ns- rest and digest response activating thorax, abdomen, pelvic regions. Afferent neurons enter spinal cord via dorsal root: transmit sensory input from periphery, synapse with interneuron"s in spinal cord. Efferent signals return via anterior motor neurons to effector organs (muscles) Pain receptors in skin transmits sensory information over afferent fibers to spinal cord.
