This experiment helps you explore the basics of electrocardiography and discover how your brain regulates heart rate through its control center in the medulla oblongata. You will learn how the specialized cells in the heart coordinate each beat with extended action potentials and how changes in activity or emotion can alter your heart’s rhythm.

The heart relies on specialized pacemaker cells to produce rhythmic electrical impulses, causing coordinated muscle contractions that pump blood throughout your body. These impulses are not as short as skeletal muscle spikes but are longer and have distinct waveforms labeled P, Q, R, S, and T. You can visualize them by placing electrodes on your skin and recording with the Human SpikerBox. The resulting waveform can be influenced by signals from your brain, which can adjust the heart rate in response to exercise, emotional states, or stress hormones such as adrenaline.

Consider whether you are recording the spontaneous cardiac action potentials initiated by pacemaker cells or the muscle potentials that follow them. Think about how your waveforms might change when you adjust the electrode positions or your posture. Reflect on how factors like caffeine, adrenaline, or recent exercise might affect what you see on screen. Imagine measuring heart rates under various conditions such as standing outside on a cold day or after sipping a warm drink, and see if you observe measurable differences in how your heart responds.