text: Another type of K channel that helps to mediate repolarization in the human atria is the SK channel, which are K channels which are activated by increases in Ca concentration. "SK channel" stands for a small conductance calcium activated potassium channel, and the channels are found in the heart. SK channels specifically act in the right atrium of the heart, and have not been found to be functionally important in the ventricles of the human heart. The channels are active during repolarization as well as during the atrial diastole phase when the current undergoes hyperpolarization. Specifically, these channels are activated when Ca binds to calmodulin (CaM) because the N-lobe of CaM interacts with the channel's S4/S5 linker to induce conformational change. When these K channels are activated, the K ions rush out of the cell during the peak of its action potential causing the cell to repolarize as the influx of Ca ions are exceeded by K ions leaving the cell continuously.