lisaR1986

Hello, I am learning about depolarization in A&P, and there is a part about it that has me stumped. My teacher writes: "At the point of stimulation, mechanical gated or chemical (ligand) gated ion channels open to threshold voltage, then voltage gated Na+ channels open and Na+ rush in..." I am confused. Why do mechanical/ligand gates open to voltage? Chemical gates open to chemical stimulus, mechanical to vibration or pressure, and voltage to voltage. Why does this threshold voltage open up these other gates, if they aren't "supposed" to be able to open to anything else? Your clarification would be MUCH appreciated!!!