Blood pressure is a measure of

A. oxygen levels in the blood.
B. the ratio of red blood cells to white blood cells.
C. how hard the heart is working.
D. the pressure exerted by hemoglobin against the vascular walls.

D.

To determine that blood pressure is a measure of the pressure exerted by hemoglobin against the vascular walls, you can use your knowledge of physiology and cardiovascular function.

Blood pressure is the force exerted by circulating blood against the walls of blood vessels. It is an important indicator of cardiovascular health and provides insights into how well the heart is functioning.

To measure blood pressure, a healthcare professional uses a device called a sphygmomanometer. This device consists of an inflatable cuff, a pressure gauge, and a stethoscope or electronic sensor. The cuff is wrapped around the upper arm and inflated so that it temporarily restricts blood flow through the brachial artery.

When the cuff is inflated, the arterial pressure surpasses the pressure exerted by the cuff. As the cuff is slowly deflated, blood flow through the artery gradually resumes and produces distinct sounds that can be heard with the stethoscope or detected by the electronic sensor. The first sound indicates the systolic blood pressure, which is the pressure exerted on the arterial walls when the heart contracts and pushes blood out. The last sound heard indicates the diastolic blood pressure, which is the pressure exerted on the arterial walls when the heart is at rest and refilling with blood.

The pressure exerted by hemoglobin against the vascular walls is a result of the pumping action of the heart and the resistance encountered by blood flow through the arteries. This pressure is commonly measured in millimeters of mercury (mmHg) and is represented by two numbers: systolic pressure over diastolic pressure (e.g., 120/80 mmHg).

Therefore, the correct answer is D. Blood pressure is a measure of the pressure exerted by hemoglobin against the vascular walls.

No, the correct answer is C. Blood pressure is a measure of how hard the heart is working. It is the force that blood exerts against the walls of blood vessels as it is pumped by the heart.