How the heart works

Your heart has 2 sides, these are divided by a wall that goes through the centre of your heart, called the septum:

• The right side of your heart transports blood to your lungs to gather oxygen.
• The left side of your heart collects the oxygen-filled blood from your lungs and transports it around your body.

Your heart is made up of chambers, valves and muscles:

• It has four chambers (think of these as rooms) – there are two chambers for each side of the heart.
• Every chamber has a valve that works just like a traffic light, only letting your blood flow one way, like a one-way street.
• The sound your heart makes is caused by your heart's valves opening and shutting, a doctor can hear this "lub-DUB" sound using a stethoscope.

 Image credit: Blausen.com wikimedia commons

What does each chamber do?

• The atria (AY-tree-uh) – 2 upper chambers that gather blood as it moves into the heart. Think of these as the ‘front doors’ of the heart. Blood low in oxygen enters first into the right atrium (through a very big vein called the vena cava).
• Blood moves from the right atrium into the right ventricle.
• The right ventricle pushes blood toward the lungs (through the pulmonary artery) – here the blood gathers oxygen.
• Oxygen-loaded blood from the lungs then moves back to the heart (through the pulmonary vein) arriving in the left atrium.
• This blood then moves from the left atrium to the left ventricle, then it is pushed out to your body (through the biggest artery in your body, the aorta).

Your heart is linked to your blood vessels (veins, arteries and capillaries):

• Veins pump blood from your body to your heart.
• Arteries move blood away from your heart to your body.
• Capillaries are tiny blood vessels linking your arteries and veins. They deliver oxygen, water, nutrients and wastes between your blood and your body tissues.
• Your blood vessels are like trains delivering food around your body: your arteries and veins are the trains, your capillaries are the delivery men.

In what order does my blood flow?

• blood moves from your body into the right side of your heart,
• then it is pumped back out to your lungs,
• your oxygen filled blood then re-enters the left side of your heart,
• finally your oxygen filled blood is transported back out to the rest of your body.

Your heart is powered by its own electrical system, this electricity is used to contract and squeeze your heart walls – pumping blood into your circulatory system and around your body.