Which vital sign measures the pressure exerted on the walls of the arteries when the heart contracts?

Systolic blood pressure is the correct choice because it specifically refers to the pressure in the arteries when the heart contracts during a heartbeat, pushing blood out into the circulatory system. This phase of the heartbeat is crucial because it indicates how effectively the heart is pumping blood and reflects the force exerted on arterial walls during this contraction.

Understanding systolic blood pressure is vital in assessing cardiovascular health, as elevated levels can indicate conditions such as hypertension, which may lead to more serious health issues if not addressed. It is also measured in millimeters of mercury (mmHg) and is represented as the higher number in a blood pressure reading, such as 120/80 mmHg, where 120 denotes the systolic pressure.

In contrast, diastolic blood pressure measures the arterial pressure when the heart is at rest between beats, while the pulse rate indicates the number of heartbeats per minute. Respiration rate, on the other hand, refers to the number of breaths a person takes in one minute and is unrelated to the pressure measurements in arteries. Understanding these distinctions helps in accurately interpreting vital signs for patient assessment and care.