B+Boutline

B+Boutline - Neurons Anatomy cell body(soma cell membrane...

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Neurons- Anatomy : cell body (soma), cell membrane, dendrites, axon hillock, axon, myelin, nodes of ranvier, buttons, synapse, dendritic spine, end foot, synaptic cleft, axon terminal Types of Neurons- Structurally: -multipolar neuron = more than 2 processes extending from its cell body (most neurons) -unipolar neuron = only 1 process extending from its cell body (sensory in DRG) -bipolar neuron = 2 processes extending from its cell body (in retina) Types of neurons – functionally -sensory (receptor) neurons- cell bodies in PNS- send neural info from the PNS to the CNS. -motor neurons- Cell body in CNS, send neural info from CNS to PNS -interneurons- receive info from other neurons and send info to other interneurons or to motorneurons Glia- TYPES OF GLIA: -astrocyte- nutritive and support function -oligodendroglial- forms myelin sheath in CNS. -scwann- form myelin sheath in PNS -radial glia-“direct” neurons to right place during development -Microglia- remove debris left by dying axon CNS vs. PNS CNS - brain and spinal cord PNS - everything else in N.S. Bundles of axons Tract Nerve Clusters of cell bodies Nuclei Ganglia Myelin sheath made by Oligodendrocyte Scwann Afferent- towards or to another structure Efferent- away from another structure Action potential- is an “all-or-none” response, because it will only occur if threshold is reached. Its amplitude is the same all along the axon and regardless of what the stimulus intensity was. -cell starts w/ more K+ inside, more Na+ and Cl- outside. When threshold (-55mV) is reached Na+ channels open (and due to electric charge Na+ goes in)-this depolarizing cause K+ channels to open (which further depolarizes). When membrane potential reaches +50 mV (peak) Na+ channels close, which repolarizes the cell-causing K+channels to close, which causes the cell to hyperpolarize (refractory period). Oscilloscope
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This note was uploaded on 03/27/2008 for the course NS 376 taught by Professor Wee during the Spring '08 term at Tulane.

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B+Boutline - Neurons Anatomy cell body(soma cell membrane...

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