BIOL 252 1st Edition Lecture 2 Outline of Last Lecture I Syllabus Overview II Functions of the Nervous System III Divisions of the Nervous System IV Structure of a Neuron Outline of Current Lecture I Structure of a Neuron II Structural Classifications III Circuits IV Organization V Supportive Cells VI Myelin VII Electrophysiology Current Lecture I II III IV V Structure of a Neuron Continued a Synaptic knob located at terminal arborization Structural Classifications a Multipolar neuron found in brain and spinal cord b Bipolar neuron olfactory cells retina inner ear c Unipolar neuron sensory neurons from skin organs to spinal cord d Anaxonic many dendrites no axon help in visual processes Circuits a Sensory afferent neurons interneurons association motor efferent neurons b Sensory unipolar c Interneuron and motor multipolar Organization a Bundles of neurons nerves PNS tracts CNS b Cluster of cell bodies ganglia PNS nuclei CNS Supportive Cells glia neuroglia a Provide physical support b Environmental control c guidance These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute d CNS VI VII i Oligodendrocytes myelin sheath attach to small part of cell ii Ependymal epithelial form barriers between nervous and non nervous tissue adjacent to cerebrospinal fluid iii Microglia smallest cells in the body clean out foreigners iv Astrocytes wrap around capillaries e PNS i Satellite cells control environment ii Schwann cells wrap around the whole cell form myelin sheath hydrophobic insulation Myelin a Occur in CNS Oligodendrocytes and PNS Schwann Electrophysiology a Extracellular i Major cation Na ii Major anion Clb Intracellular i Major cation K ii Major anion proteins HPO42c Cell membrane has a potential difference in charge produces current flow of electrons d Resting Membrane Potential 70 mV i ii Why does it get that way 1 Selective permeability a Plasma membrane is hydrophobic b Proteins and channels allow things to enter c Semipermeable to K 2 Chemical diffusion a Difference in concentration pushes K out creating positive charge outside 3 Electrical attraction repulsion a Created positive exterior repels further K movement out of cell b Places limit iii Maintaining RMP 1 Electrical forces cause force in 2 Chemical diffusion gradient force out 3 K diffusion is in dynamic equilibrium self stabilizing 4 Na K ATPase pump a Pumps 3Na out b Keeps amount Na in cell to minimum c Pumps 2K in d Maintains chemical diffusion gradients e Generates electrical potential i Adding net 1 charge to outside of cell
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