Blood pressure
From Simple English Wikipedia, the free encyclopedia
Blood pressure is the pressure made by the blood at right angles of the walls of blood vessels. Unless otherwise stated, "blood pressure" refers to systemic arterial blood pressure, which is the pressure in larger arteries delivering blood to body parts other than the lungs, for example the brachial artery in the arm. The blood pressure varies. It is measured in millietres of mercury. Blood pressure is higher in arteries than it is in other blood vessels. Blood pressure is always measured in millimeters of mercury (mmHg).
Systolic pressure is the first number given in blood pressure readings. It is the peak pressure in the arteries during the cardiac cycle. The diastolic pressure is the second number given in a blood pressure reading, and it is the pressure at the resting phase of the cardiac cycle. The mean arterial pressure and pulse pressure are other important quantities.
Typical values for a resting, healthy adult human are approximately 120 mmHg systolic and 80 mmHg diastolic (written as 120/80 mmHg), but this can be very different for each person. Blood pressure readings change naturally throughout the day (in a circadian rhythm); they also change in response to stress, nutritional factors, drugs, or disease.
