Action Potential Propagation

Ions Involved in Action Potential Propagation Essay.

Nerve and muscle functions involve electrical conduction. However, nerves and muscle are not like electrical wires. Nerve and muscle cells are poor conductors of classical electrical current flow; such current dies out within a few millimeters. Signal transport (Action Potentials), does travel from one end of a nerve to the other. There is no diminishment of the signal, independent of the length of the cell (unlike a wire), and energy is required in the energy transport process itself. Action potential would go from toe to brain in about 1 sec = 100 m.sec.. The resting membrane potential of a nerve (or any cell) is about -70 "millivolts". The minus means that it's negative on the inside and positive on the outside of the cell. Like a voltage can be measured by placing one electrode of a voltmeter inside a cell and the second electrode outside the cell.

Action potential is defined as, an explosive change in electrical activity. For example, a sudden change in the membrane potential. The action potential is the signal that is transported along a nerve or muscle cell. An action potential is induced by a stimulus. The stimulus is often an electrical change itself, but for some cells it can also be chemical like taste, drugs, smell, or "mechanical" (ex. touch, pressure, sound), light (vision), temperature (hot and cold receptors...)...

-The signal travels as a wave down the cell.

Action potentials are not extremely important in understanding a brain and nervous system, but they're also good in understanding senses, muscles, hormone function, and drug responses.

The membrane potential is caused by active transport along with some return 'leakage' of ions. The depolarization would happen if Na+ flows inward because of the diffusion gradient and ion gradient. Therefor the positive charge on the outside would drop. And Hyperpolarization is going to take place when the K+ does it thing flowing outward, because of that diffusion gradient. Again, therefore the positive charge on the outside would become, now, greater.

These gates do open and close, apparently they're caused to open by electrical changes. These electrical changes correspond to 'stimulus'. When they do that, the opening and closing follows a pretty much set pattern. While the gates are