There are blood vessels all over the body. Some are easy to see, because they are close to the skin surface. Most blood vessels cannot be seen because they are buried deep among the muscles and other tissues. If you press your fingertips against some blood vessels you will feel a regular throbbing movement. This is called the pulse. Blood vessels which have a pulse are called arteries. They carry blood away from the heart. There are various places on the body where the pulse can be felt. The pulse is usually found on a person’s left wrist.

Each pulse throb is caused by a sudden rise in the pressure of the blood in the artery. What do you think causes this sudden rise in pressure of the blood in the artery? Okey, here’s another question: what makes the hot water move through the pipes and radiators of a modern central heating system?

Blood vessels are like pipes. The blood is like water. A pump is needed to move the blood through the blood vessels. This pump is the heart. Every time it beats, the heart forces blood out through the arteries. With each heartbeat there is a rise in pressure. This causes the arteries to swell, which is what you can feel at the pulse points. This explains why pulse rate is the same as heartbeat rate.

Your heart is the best pump ever made. In most people, the heart works all the time, without repair or servicing, for the whole of their lives. The speed at which it beats can be changed, in a few seconds, from about 70 to 140 beats per minute or more. Rates of 200 or more occur during violent exercise. Most important of all, the heart does not damage the blood as this passes through it. Blood is a delicate thing. No man has ever built a pump which is so gentle, so strong and so reliable. But the heart can go wrong if it is not looked after properly.