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  • Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics

  • in 2 minutes or less. In this installment I will discuss membrane potential.

  • Membrane potential refers to the difference in electrical charge between the inside and

  • the outside of a neuron. This is the plasma or cell membrane of the neuron. It separates

  • the inside of the cell from the outside environment; well say this is the inside and this is

  • the outside of the neuron. The difference in electrical charge develops due to the grouping

  • of ions on the inside and outside of the membrane. Ions are atoms that have either lost or gained

  • electrons and thus have a positive or negative charge.

  • There are several ions that play an important role in the membrane potential of neurons.

  • There are positively charged sodium ions, represented by these blue circles and negatively

  • charged chloride ions, represented by these green circles. When a neuron is at rest, the

  • sodium ions and chloride ions are more prevalent outside of the cell. There are also positively

  • charged potassium ions, represented by these yellow circles and various negatively charged

  • ions, often referred to as organic anions represented by these grey circles (anion is

  • simply a term for a negatively charged ion). When a neuron is at rest, the potassium ions

  • and organic anions are more prevalent inside the cell. At rest, the inside of the neuron

  • is more negatively charged than the outside, causing the resting membrane potential of

  • an average neuron to be around -70 millivolts.

  • One way this potential is maintained is through a mechanism known as the sodium-potassium

  • pump. This is a transport protein that uses energy to constantly pump three sodium ions

  • out of the cell while at the same time pumping two potassium ions into the cell. Because

  • there are more positive ions being pumped out than in, it helps to keep the membrane

  • potential negative.

  • Unlike other ions, potassium tends to move fairly easily across the cell membrane through

  • ion channels, which are membrane spanning proteins that allow ions to pass through.

  • Potassium will pass out of the neuron until it reaches the point where it is at an equilibrium

  • - when forces like diffusion aren’t pushing it in one direction or the other. At this

  • point, the membrane potential of the neuron is around -65 to -70 mV, which is known as

  • the resting membrane potential.

Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics


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B2 中上級

2 分間の神経科学:膜電位 (2-Minute Neuroscience: Membrane Potential)

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    Cheng-Hong Liu に公開 2021 年 01 月 14 日