Chapter 3 I. Neuron Doctrine and Brain Cells A. Cells are distinct structurally, metabolically, and functionally in the brain II. Types of Neurons A. Motor- send info to neurons B. Sensory- send info to sensory receptors in the brain III. Parts of a Neuron A. Soma- cell body, contains nucleus and other organelles B. Dendrites- input of the cell, receives info from other neurons C. Axon- sends info from soma to terminals D. Presynaptic terminals- output of cells, translates info into chemical signals for transmission IV. Glial Cells A. Schwann cells B. Oligodendrocyte C. Astrocyte D. Microglia V. Electrical Potentials A. Resting- voltage difference inside and outside of cell B. Action- electrical difference inside and outside of cell when it is transmitting a signal C. Na/K Pump- pumps K into cell, Na out (2 in, 3 out) i. At rest, K diffuse out of cell ii. intracellular proteins- negatively charged VI. Action Potentials A. Communication between cells B. Inputs from other cells causes change in voltage VII. Local Anesthetics A. Block Na channels B. Also prevent motor output VIII. Strength of Action Potentials A. Like a toilet- no matter how strong the stimulus, action potential stays the same (no matter how hard you flush, same output) B. Once Na channels open, they open other Na channels C. Once the threshold is crossed, action potential goes full strength the length of the axon D. Neuron has refractory period after it fires action potential
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