1 . The Sodium/potassium ATPase pump has been called the “center of the universe
ID: 85527 • Letter: 1
Question
1. The Sodium/potassium ATPase pump has been called the “center of the universe.” Why do you think that is? Include electrochemical gradients, resting membrane potentials and ion movement. Start by telling the typical intracellular and extracellular concentrations of sodium and potassium. Include examples of three different places in the body that you know about ion movement and how the sodium/potassium ATPase pump plays a role (ie. sodium reabsorption in the nephron, neurons, pacemaker cells in the heart, absorption in the GI tract…and many others). feel free to include illustrations.
Explanation / Answer
The ionic movement across the cell membrane plays a crucial role in maintenance of multiple vital functions in the cell. Most of these ionic movements are based upon differential and unidirectional movements of sodium and potassium ions in the cells. For example, the excitatory cells such as neurons are a very good example of ionic movement across them. The neurons comprise of membrane bound voltage-gated channels in their membranes which open and close with respect to the chances in membrane potential of the neuronal surface with respect to the exterior.
Initially, there are large number of sodium ions outside whereas large number of potassium ions inside the neuron with respect to the periphery. At this stage, the neuron is polarized in nature. As a stimulus is applied, the voltage-gated sodium and potassium ions open up which mediate inward movement of sodium ions and outward movement of potassium ions. This causes the membrane to depolarize and thus excite. This brings about a physiological response by the neuron as well. Further, after the excitation potential dampens, the neuron again reaches to the stage of high sodium outside and low potassium inside, thus getting re-polarized.
In this way, the movement of various ions brings about excitation and transmission of electro-chemical information across the cells and communicate with each other.
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