The arteries are the large blood vessels that carry blood from the heart to all the organs and muscles of the body, to give them the energy and oxygen they need. The arteries manage the flow of blood by controlling the speed and direction it flows in. Because the blood inside the arteries is being pushed round by the heart, the blood pushes against the insides of the artery walls. This pushing is your blood pressure.
To cope with this pressure, the artery walls contain tiny muscles to hold them in shape and allow them to become wider or narrower. Opening and closing different arteries affects your blood pressure. The more narrow your arteries are, the less space there is for your blood to flow in and the harder it pushes against the arteries walls.
Arteries carry blood away from the heart.
The blood in the arteries is under pressure because of the contractions of the heart muscles. This allows the blood to reach all parts of the body. You can see how the heart pumps the blood to the lungs and rest of the body by studying this animation: In order to see this content you need to have both enabled and installed. Visit Blood pressure is measured in millimetres of mercury, mmHg.
There are two measurements: systolic pressure – the higher measurement when the heart beats, pushing blood through the arteries, and diastolic pressure A young, fit person may have a blood pressure of about 120 over 70, which means their systolic pressure is 120 mmHg, and their diastolic pressure 70 mmHg. Blood pressure varies with age. It also varies with lifestyle factors such as: