Final answer:
The cardiac action potential involves a prepotential phase, a rapid influx of Ca2+, and an outflux of K+ in conductive cells, while contractile cells' action potential includes an extended plateau phase. The ECG features such as the P wave, QRS complex, and T wave correlate to atrial and ventricular depolarization and repolarization, respectively. These electrical activities ensure the heart's effective pumping and coordination of the cardiac cycle.
Step-by-step explanation:
The cardiac action potential (AP) and its underlying currents play a crucial role in the functioning of the heart. The conductive cells of the heart generate a prepotential phase, followed by a rapid influx of Ca2+ and outflux of K+, which sets the heart rate. This is followed by the contractile cells' action potential, which features an extended plateau phase providing an extended refractory period that is essential for complete heart contraction and effective blood pumping.
Recognizable points on the electrocardiogram (ECG) include the P wave, indicating atrial depolarization; the QRS complex, indicating ventricular depolarization; and the T wave, which reveals ventricular repolarization. Each cardiac cycle consists of a full relaxation and contraction of the atria and ventricles, allowing the heart to pump blood effectively. This cycle is further demonstrated by the regular fluctuation of arterial blood pressure, with systolic pressure peaking shortly after the QRS complex.
Overall, the heart's electrophysiology, including action potentials, ion movements, and their coordination with mechanical contractions, is critical for maintaining the heart's rhythm and ensuring effective blood circulation throughout the body.