Our circulation is similar to a highly sophisticated form of plumbing - blood has 'flow' and arteries are 'pipes.' A basic law of physics gives rise to our blood flow, and this law also applies in a garden hose pipe.

Blood flows through our body because of a difference in pressure.

Our blood pressure is highest at the start of its journey from our heart - when it enters the aorta - and it is lowest at the end of its journey along progressively smaller branches of arteries. That pressure difference is what causes blood to flow around our bodies.

Arteries affect blood pressure in a similar way to the physical properties of a garden hose pipe affecting water pressure. Constricting the pipe increases pressure at the point of constriction.

Without the elastic nature of the artery walls, for example, the pressure of the blood would fall away more quickly as it is pumped from the heart.

While the heart creates the maximum pressure, the properties of the arteries are just as important to maintaining it and allowing blood to flow throughout the body.

The condition of the arteries affects blood pressure and flow, and narrowing of the arteries can eventually block the supply altogether, leading to dangerous conditions including stroke and heart attack.