When you palpate a pulse, what are you actually feeling?

When palpating a pulse, you are primarily feeling the contraction of the left ventricle. The pulse represents the wave of pressure that is created when the left ventricle contracts and pumps blood into the aorta and subsequently into the systemic circulation. This contraction forces blood into the arteries, causing the walls of the arteries to expand and create a palpable pressure wave that can be felt at various pulse points in the body.

The expansion of blood vessels occurs in response to the increased pressure from the heartbeat, but it is the contraction of the left ventricle that initiates this process and creates the pulse. The other options refer to different physiological processes; for example, movement of blood through veins is a result of overall circulation and should not be confused with the immediate sensation of a pulse, which is specifically tied to arterial pressure from ventricular contraction. Similarly, the heartbeat from the right atrium refers to the initiation of electrical impulses but does not directly correspond to the pulse felt in the arteries. The critical factor in determining a pulse is the left ventricle's role in propelling blood into the arterial system.