Your circulatory system is amazing. If you stretched out all of your blood vessels, they would extend to over 60,000 miles! The heart itself is quite small, weighing only about 1 pound. It has its own electrical supply -and will continue beating, even after it has been separated from the body. A human heart beats around 100 000 times per day, over a lifetime it could be beat more than 3 billion times! The American pygmy shrew, which is the smallest mammal – has the fastest heartbeat – around 1,200 beats per minute. Also, the blood pressure in your heart is high enough to squirt your blood over 30 feet!!

You could argue that the most amazing heart belongs to the zebra fish. The heart of a zebra fish is brilliant at regenerating. It repairs injuries to itself, until it is nearly as good as new! This is why scientists study the fish, to discover possible treatments for the human heart.

If you are studying GCSE Science, you need to understand the structure of the heart, and be able to describe the route blood travels through the heart. For help with this – try our new guide “How to work with the Circulatory System”. It includes questions for you to try, and answers to check your understanding.