活動電位
Electrical fields have been shown to influence a gamut of cellular processes and responses. Animals, plants, and bacteria have a range of responses to electrical structures. The electrophysiology in humans consists of the nervous system regulating our actions and behaviors through controlled responses. Action potentials in our nerves and our heart are regulated based on our sodium and potassium levels. Pressure applied to our skin opens up mechanosensitive sodium channels. With the right amount of stimulus it can cause the action potential to reach threshold and cause an influx of sodium during the depolarization phase. After a couple of seconds, the membrane potential becomes positive and causes potassium ions to exit the cell during the repolarization phase and go below the threshold level into the hyperpolarization phase. The leaky sodium and potassium channels bring back the membrane potential to resting. The electrical signaling in humans allows us to perform rapid movements during periods of stress and anxiety. Similarly in plants, electrotropism is used in plant defense signaling and growth.