PSY100Y5 Lecture Notes - Lecture 2: Efferent Nerve Fiber, Membrane Potential, Anaphylaxis
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PSY100Y5 Full Course Notes
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Myelin insulates the nerve cell, speeds up conduction of nerve messages. 70mv stored in cell bodies ready to be activated by neurotransmitters. Afferent (sensory neurons), efferent neurons (motor signals, outgoing signals to muscles) Myelin sheaths are coated more heavily on different nerves such as pain pathways that allow us to react quickly. Belief that myelin accrues more as it is used more. Stimulation of the nerve membrane can open ion channels in the membrane. Na+ ions flowing in will depolarize the membrane from -70mv to -60mv. K+ ions flowing out of membrane will hyperpolarize the membrane from -70 mv to -90mv. Graded potentials are generated at the dendrites and are conducted along the membrane to the axon hillcock. If the summated activity at the axon hillcock raises the membrane potential past threshold, an action potential will occur (neural impulse) During the action potential, na+ ions flow into the cell raising the membrane potential to 40.
