BIOL 252 1st Edition Lecture 2 Outline of Last Lecture I. Syllabus OverviewII. Functions of the Nervous SystemIII. Divisions of the Nervous SystemIV. Structure of a NeuronOutline of Current LectureI. Structure of a NeuronII. Structural ClassificationsIII. CircuitsIV. OrganizationV. Supportive CellsVI. MyelinVII. ElectrophysiologyCurrent LectureI. Structure of a Neuron (Continued)a. Synaptic knob-located at terminal arborizationII. Structural Classificationsa. Multipolar neuron-found in brain and spinal cordb. Bipolar neuron-olfactory cells, retina, inner earc. Unipolar neuron-sensory neurons from skin/organs to spinal cordd. Anaxonic-many dendrites, no axon; help in visual processesIII. Circuitsa. Sensory (afferent) neurons => interneurons (association) => motor (efferent) neuronsb. Sensory = unipolarc. Interneuron and motor = multipolarIV. Organizationa. Bundles of neurons = nerves (PNS) / tracts (CNS)b. Cluster of cell bodies = ganglia (PNS) / nuclei (CNS)V. Supportive Cells = glia, neurogliaa. Provide physical supportb. Environmental controlc. guidanceThese 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. CNSi. Oligodendrocytes: myelin sheath, attach to small part of cellii. Ependymal: epithelial, form barriers between nervous and non-nervous tissue, adjacent to cerebrospinal fluidiii. Microglia: smallest cells in the body, clean out foreignersiv. Astrocytes: wrap around capillariese. PNSi. Satellite cells: control environmentii. Schwann cells: wrap around the whole cell, form myelin sheath = hydrophobic insulationVI. Myelina. Occur in CNS (Oligodendrocytes) and PNS (Schwann)VII. Electrophysiologya. Extracellulari. Major cation: Na+ii. Major anion: Cl-b. Intracellulari. Major cation: K+ii. Major anion: proteins, HPO42-c. Cell membrane has a potential (difference in charge) => produces current (flow ofelectrons)d. Resting Membrane Potential (-70 mV)i. ii. Why does it get that way?1. Selective permeabilitya. Plasma membrane is hydrophobicb. Proteins and channels allow things to enterc. Semipermeable to K+2. Chemical diffusiona. Difference in concentration pushes K+ out, creating positive charge outside3. Electrical attraction/repulsiona. Created positive exterior, repels further K+ movement out of cellb. Places limitiii. Maintaining RMP1. Electrical forces cause force in2. Chemical diffusion gradient force out3. *K+ diffusion is in dynamic equilibrium (self-stabilizing)4. *Na+/K+ ATPase pumpa. Pumps 3Na+ out b. Keeps amount Na+ in cell to minimumc. Pumps 2K+ ind. Maintains chemical diffusion gradientse. Generates electrical potentiali. Adding net +1 charge to outside of
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