Physiology 2130 Lecture Notes - Lecture 4: Electrochemical Gradient, Axon Terminal, Membrane Potential
12 Nov 2015
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4. 2, 4. 3 introduction: we have learned that virtually all cells in the body have a membrane potentials, inside being electrically negative relative to the extracellular fluid, we have also learned how this membrane potential is established and maintained by electrochemical gradients of the major intracellular and extracellular ions, nerve cells and muscle cells are considered excitable because they canuse the resting membrane potential to generate an electrochemical impulse called action potential, the action potential is considered to be the language of the nervous system because this is the way nerve cells communicate with one another. Axon: axon: carries outgoing signal to the target cell in the form of an action potential, myelin sheath: (only present when myelinated) layered phospholipid membrane sheath wrapped tightly around the axon, it acts insulator for the axon forcing the ionic changes that comprises the action potential to take places only at small exposed regions of the axon, known as the nodes of ranvier.
