What is blood pressure primarily defined as?

Blood pressure is primarily defined as the force exerted by blood on the walls of the arteries. This definition is essential because it reflects the pressure that the circulating blood exerts within the arterial system during the cardiac cycle. Blood pressure readings are taken using two measurements: systolic pressure (the pressure in the arteries when the heart beats) and diastolic pressure (the pressure in the arteries when the heart is at rest between beats). This distinction is critical in understanding cardiovascular health, as elevated or low blood pressure within the arteries can indicate various health conditions, including hypertension or hypotension.

The other options do not accurately represent the primary definition of blood pressure. The force exerted by blood on the walls of the veins relates more to venous pressure, which is different from arterial pressure. The volume of blood pumped by the heart in a minute refers to cardiac output, another important cardiovascular measurement but not a definition of blood pressure itself. Finally, the amount of oxygen carried in the bloodstream pertains to oxygen saturation and hemoglobin levels, which are distinct concepts in the study of cardiovascular and respiratory physiology.