LIFESCI 2 Lecture Notes - Lecture 11: Axon Hillock, Myelin, Efferent Nerve Fiber
11 Aug 2017
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Nervous system vid: neurons make up nervous system; transmits electrical & chemical signals. Generate & conduct major electrical signals away from soma. Schwann cells produce myelin sheaths that insulate the axon (speed) Pre-synaptic & post-synaptic neuron function by processing electrical activities. Both chemical & electrical driving force (+ve attracted to ve charge: at rest: leak channels (not gated) for na+ & k+ Passive process: na+ in, k+ out (chemical driving force, diffusion) active transport: na-k pump (maintain gradient & driving force; excitability) limited permeability. Always ion movement, but doesn"t affect at large terminology. Depolarization: when membrane potential is less negative than resting potential resting potential: -70mv. Repolarization: when a membrane potential has been depolarized (or hyperpolarized), returns to its resting value. Hyperpolarization: when membrane potential is more negative than resting potential (about - Voltage gated na+ channel & k+ channel: voltage gated na+ channel. Inactivated, peak to resting potential (30~-70mv: voltage gated k+ channel.
