_Y_+9
_IMG_48_13ActionPotGenerat3.jpg
<strong>Rising phase of the action potential.</strong><br>
<strong>Depolarization</strong> opens more <b>Na<sup>+</sup></b> channels;
the <b>K<sup>+</sup></b> channels remain closed.<br>
If the <strong>depolarization</strong> reaches the <strong>threshold</strong>, it triggers an <b>action potential</b>.