Ion_Movement

Ion Movement Transmembrane Potential All of our cells in our body are under constant changes. A portion of these changes is in response to a chemical change either in the extracellular fluid around the cell or inside the cell its self. Here I will examine the movement of ions across a typical cell membrane. An undisturbed cell or inactive cell is said to be at its resting potential. A typical charge of a neuron at its resting potential is –70mv. It is the job of membrane channels to affect the transmembrane potential and ultimately alter the activity of the cell. Membrane channels are in control of ion movement across the cell membrane. In most cases of transmembrane potential it is the movement of sodium and potassium ions that create the most changes and are the most effective. Generally, there are two types of membrane channels: passive or leaky channels and active or gated channels. Passive channels are always open, therefore, allowing a constant exchange of ions between the extracellular fluid and the cytosol. Active channels open or close when stimulated by a specific stimulus. There are three stages or positions for an active channel channels, channel, potential, cell, membrane, regulated, open, gated, voltage, transmembrane, changes, type, sodium, resting, movement, active, action, types, specific, sensory, opening, mechanically, ions, closed, close, across, voltage-regulated, ultimately, typical, two, three, stage, rest, response, potassium