Inward-rectifier potassium channels are specialized proteins found in cell membranes that allow potassium ions to flow into the cell more easily than out. They play a crucial role in maintaining the cell's resting membrane potential and regulating electrical activity in various tissues, including the heart and brain. These channels help stabilize the cell's internal environment by controlling potassium levels. These channels are characterized by their unique ability to conduct potassium ions preferentially in one direction, hence the name "inward-rectifier." They are influenced by factors such as voltage and the concentration of other ions, including magnesium and calcium. Dysfunction in these channels can lead to various health issues, including cardiac arrhythmias.