Action potential, in nerves

You will be expected to have an understanding of action potentials in nerves, cardiac pacemaker cells and cardiac conduction pathways. 

Sodium channels are responsible for the propagation of action potentials in nerve fibers. Local anesthetics are blockers of sodium channels. They will thus intercept the propagation of action potentials along nerve fibers and in this way, among other things, prevent perception of pain. 

In living cells, ion channels and energy-dependent pumping mechanisms (with more or less specificity) facilitate or catalyze the permeation of certain ions in one direction or the other across the lipid bilayers that constitute the cell membranes. This mechanism makes the permeation of certain ions several orders of magnitude faster than the permeation of others which thereby accentuates the transmembrane potentials discussed above. These processes are particularly important in the creation and the transmission of the action potential in nerves. 

Blocks action potentials in nerves by preventing sodium flow, reducing nerve conduction... 

Voltage-Gated Ion Channels and the Propagation of Action Potentials in Nerve Cells... 

In this example, the Na concentration gradient and the membrane electric potential contribute almost equally to the total AG for transport of Na Ions. Since AG Is <0, the inward movement of Na Ions Is thermodynamically favored. As discussed in the next section, certain cotransport proteins use the inward movement of Na to power the uphill movement of other ions and several types of small molecules into or out of animal cells. The rapid, energetically favorable movement of Na ions through gated Na channels also is critical in generating action potentials in nerve and muscle cells. 

Winfree has (1974a) presented an interesting model of excitable kinetics, f(x), and computed spiral wave solutions to Eq. (10) in two spatial dimensions. He borrows the kinetics from the theory of action potentials in nerve membranes (FitzHugh, 1961 McKean, 1970)... 

One electrotherapy modality is electrical stimulation (ES). This is a technique in which an electrical current pulse flows between an active (cathode) and indifferent (anode) electrode, causing depolarization of the cellular membranes and generation of action potentials in nerves and muscle contraction. 

Tetrodotoxin 17, produced by a number of marine organisms, including puffer fish and other members of Tetraodontiformes, is a potent neurotoxin that is approximately ten times more poisonous than potassium cyanide. It too blocks the action potential in nerves by binding to the voltage-gated, fast sodium channels in nerve cell membranes thereby preventing the nerve cells from firing. 

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