Theme 3. Action potential of nervous fiber and other excitable tissues. Molecular mechanisms.Purpose:To understand the mechanisms of arising of action biopotentials. To know the methods of research of biopotentials arising in living organism. Plan of the lecture: 1. Generation of action potential. 2. Methods of studying of molecular mechanisms of electromechanical potentials of membranes. 3. Propagation of the nervous impulse along the excitable fiber. Theses of the lecture: Arising of biological potentials mainly is caused by the inequality of the ions concentration in a system. There are following biopotentials: diffuse, membraneous, phasic (interphasic), redox. Membrane potential depends on the temperature and the gradient concentration of ions that diffuse through the membrane. The value of the membrane potential is determined by the Nernst equation. Actually, the membrane potential is the result of diffusion of three types of ions: potassium, sodium and chlorine and it is determined by Goldman equation. Occurring at the excitation of cells and is caused by the changing of membranes conductivity is called action potential. Propagation of action potential along the nervous fiber is determined by the telegrapher’s equations. Illustrative material: “Power Point” presentation (lecture 5).
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