The human heart is a muscle that lies left of the chest. It has about the size of a fist. The heart is like a pump that sends blood around your body. The blood gives you the oxygen you need. An average heart pumps about 70 millilitres of blood into your body with every beat. That’s about 5 litres every minute or about 7200 litres every day.
PARTS OF THE HEART
The heart is made up of 4 chambers. There are two chambers on each side of the heart. The top two chambers are called the atria. They fill with blood. The two chambers at the bottom of the heart are called ventricles. Their job is to squirt out the blood. In the middle of the heart there is a thick muscle called the septum that separates the left and the right side.
The atria and ventricles work together. The atria fill with blood and when they are full they let the blood into the ventricles. When these ventricles pump the blood out of the heart, the atria fill up again and the whole process starts again.
There are valves in the heart that make sure that the blood is pumped in the right direction. When the heart contracts, it pumps blood from its chambers into the body. Then the heart muscle relaxes and lets the chambers fill up.
Parts of the human heart
BLOOD CIRCULATION
Every cell in your body needs oxygen to live. The role of the heart is to send blood that is full of oxygen to all the cells in your body.
The passageways that carry this blood are called blood vessels. Arteries carry oxygen-rich blood to the cells that need it. The largest artery is the aorta. Veins carry blood back to the heart again. It is pumped into your lungs where it picks up oxygen and then goes back to your heart, from where it is pumped back again into your body.
It only takes about 20 seconds to pump blood to every cell of your body.
YOUR HEART BEAT
Even though your heart is inside you, you can see it work by feeling your pulse. You can find your pulse in many parts of your body. It’s best to press your finger on the inside of your hand, just below the thumb. You can feel a small beat under your skin. This is caused by the contraction of your heart.
When you rest or sleep your heart does not beat that fast—about 60 to 80 beats a minute. When you run around a lot your heart pumps more blood into your body—maybe up to 200 times a minute.
CHANGING HEART RATES
As people grow older their heart rates change. A newborn baby has a heart rate of about 130, a three-year old has about 100 and an eight-year old’s heart beats about 90 times a minute. An adult has a heart rate of about 70 to 80. The older you get the slower your heart beats.
HEART ATTACK
Your heart is probably the most important part of your body. If it stops pumping blood you cannot survive.
The greatest danger for your heart is a heart attack. It happens suddenly and is like an explosion. When the heart stops pumping blood, muscles must die because they cannot get any oxygen.
In some cases blood is not able to flow through the blood vessels because they are clogged up. So the heart does not get enough blood to work. Chest pain may be a possible warning sign of an upcoming heart attack.
HOW TO KEEP YOUR HEART HEALTHY
Most people are born with a healthy heart, but it’s important to keep it healthy.
· Your heart is a muscle. It needs exercise. About twenty minutes of exercise a day will keep it strong and healthy.
· Eat different kinds of food and don’t eat too much fat.
· Smoking is bad for your heart.
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