What causes the rhythmic beats felt as a pulse?

The correct answer highlights that the rhythmic beats felt as a pulse are primarily caused by waves of blood moving through arteries. As the heart pumps, it ejects blood into the arteries, creating a pressure wave that travels along the arterial walls. This pressure wave is what we perceive as a pulse at various points on the body, such as the wrist or neck.

The contraction of the heart muscles is fundamental to initiating the heartbeat and driving the blood flow, but it is the subsequent movement of blood through the arteries that generates the pulse sensation. While the movement of blood through veins is vital for returning blood to the heart, it does not contribute to the characteristic pulse that is felt in the arteries. Similarly, the filling of the chambers of the heart is part of the cardiac cycle but does not create the pulse sensation directly; instead, it is the contraction of the heart that leads to the ejection of blood and the formation of that pulse wave in the arteries.