Question

What is the role of potassium in muscle contraction?

Answer 1

Potassium is important for electrical impulses that trigger muscles via nerves.

Explanation:

Muscles contract because of electrical impulses from nerves. As potassium is important for the nervous system, it is also important for muscle contraction.

Electrical impulses travel along a neuron by a chain reaction caused by positively charged sodium ions travelling across the neuron's cell membrane. As the interior is usually negative, this causes a change in charge and triggers the adjacent area - leading to an impulse travelling along it.

In order for this impulse to occur, there needs to be an action potential across the cell membrane - this means that one side is positive and the other negative. Therefore, in it's normal state, a neuron will have positive sodium ions on the outside of the cell and negative chlorine ions inside (note that this is not exclusive, there will be both ions on both sides but in different concentrations).

This is where potassium comes in as the potassium sodium pumps use two potassium ions to swap with three sodium ions. This eventually leads to the sodium being swapped iover to the exterior to create a positive overall charge.

This website shows a very useful animation:)
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