Your heart is a kind of pump made of muscle. It sucks in blood from the veins and then forces it out through the arteries.
It weighs only 300 grams.
It beats about 60 or 70 times a minute when you are resting, much more when you are active.
It pumps at least 5 litres of blood around your body every minute. During an average lifetime it beats 2,500,000,000 times and pumps 340 million litres of blood.
