The heart is an amazing organ. It’s the first in the body to start functioning during embryonic life and from that early stage it beats relentlessly – contracting about 70 times a minute, 100,000 times a day, two and a half billion times a lifetime.
It pumps 70 ml to 100 ml of blood per beat, carrying oxygen and nutrients to all your body’s organs and tissues.
The heart has a left side and a right side, divided by a wall of muscle. Each side has a small collecting chamber called an atrium, and a larger lower pumping chamber called a ventricle. Between each pair of chambers is a valve which only lets the blood flow in one direction. There are also valves between each ventricle and the artery it feeds.
The right side of the heart collects blood that has been depleted of oxygen as it returns from the body. This blood is pumped through the pulmonary artery to the lungs, where the oxygen is replenished. It then returns to the left side of the heart, where it is pumped through the aorta and out to the body again. The left ventricle is larger and thicker than the right ventricle, so it can produce the higher pressure needed to pump blood round the body.
Blood moves through the body along a network of vessels called arteries, veins and capillaries. Arteries carry blood away from the heart, while veins carry blood towards the heart. Capillaries, which are too small to be seen with the naked eye, carry oxygen and nutrient rich blood from the arteries to the tissue cells and then back into the veins.
This constant flow of blood – from the heart to the lungs, back to the heart, out to the body and back to the heart – takes about 23 seconds.
The whole system is known as your Cardiovascular System, which comes from the Greek word cardiac meaning heart and the Latin word vasculum meaning vessel.
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