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Body Talk

The 'beat' that keeps you alive!

When someone says or does something that hurts you very much, haven't you felt as though they have broken your heart? What about all those novels and songs that centre around broken hearts?

You must have heard many things about hearts and heartaches. Did you know that in the good old days, people even thought that their 'emotions came from their hearts'?

This must be because the heart beats faster when a person is scared or excited. But it has been established that emotions come from the brain, and that the brain tells the heart what to do. So what's the heart really up to? How does it keep busy? What does it look like? Let's find out.

The heart is one of the most important organs in the human body. Did you know that your heart is really a muscle located a little to the left of the middle of your chest, about the size of your fist? The heart sends blood around your body. The blood provides your body with the oxygen and nutrients it needs. It also carries away waste.

Your heart is like a pump, or two pumps in one. The right side of your heart receives blood from the body, and pumps it to the lungs, the organs which we featured last week. The left side of the heart does the exact opposite: it receives blood from the lungs and pumps it out to the body.

Have you ever wondered how the heart beats? Before each beat, your heart fills with blood. Then its muscle contracts to squirt the blood along. When the heart contracts, it squeezes. Your heart does this all day and all night, all the time. The heart is one hard worker!

The heart is made up of four different blood-filled areas, and each of these areas is called a chamber. There are two chambers on each side of the heart. One chamber is on the top and one chamber is on the bottom.

The two chambers on top are called the atria. If you're talking only about one, then it is called an atrium. The atria are the chambers that fill with the blood returning to the heart from the body and lungs. The heart has a left atrium and a right atrium.

The two chambers on the bottom are called the ventricles. The heart has a left ventricle and a right ventricle. Their job is to squirt out the blood to the body and lungs. Running down the middle of the heart is a thick wall of muscle called the septum. The septum separates the left side and the right side of the heart.

The atria and ventricles work as a team - the atria fill with blood, then dump it into the ventricles. The ventricles then squeeze, pumping blood out of the heart.

While the ventricles are squeezing, the atria refill and get ready for the next contraction. So, when the blood gets pumped, how does it know which way to go?

Well, your blood relies on four special valves inside the heart. Two of the heart valves are the mitral valve and the tricuspid valve. They let blood flow from the atria to the ventricles. The other two are called the aortic valve and pulmonary valve, and they're in charge of controlling the flow as the blood leaves the heart. These valves all work to keep the blood flowing forward. They open up to let the blood move ahead, then they close quickly to keep the blood from flowing backward.

Blood just doesn't slosh around your body, once it leaves the heart. It moves through many tubes called arteries and veins, which together are called blood vessels. These blood vessels are attached to the heart. The blood vessels that carry blood away from the heart are called arteries. The ones that carry blood back to the heart are called veins.

The movement of the blood through the heart and around the body is called circulation. It only takes less than 60 seconds to pump blood to every cell in your body.

Your body needs this steady supply of blood to keep it working right. Blood delivers oxygen to all the body's cells. To stay alive, a person needs healthy, living cells. Without oxygen, these cells would die. If that oxygen-rich blood doesn't circulate as it should, a person could die.

The left side of your heart sends that oxygen-rich blood out to the body. The body takes the oxygen out of the blood and uses it in your body's cells. When the cells use the oxygen, they make carbon dioxide and other stuff that gets carried away by the blood.

Each time the blood circulates from the heart out to the body, about 20 per cent (one fifth) of it goes through the kidneys. The kidneys filter out some of the waste, before the blood heads back to the heart.

The returning blood enters the right side of the heart. It takes the blood to the lungs for a little freshening up.

Carbon dioxide is left in the lungs to be removed when we exhale. What's next? An inhale, of course, and a fresh breath of oxygen that can enter the blood to start the process again. And remember, it all happens in about a minute!

Compiled by: Chamitha

More on the heart next week.

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Keep your heart happy

Most kids are born with a healthy heart and it's important to keep yours in good shape. Here are some things that you can do to help keep your heart happy:

* Remember that your heart is a muscle. If you want it to be strong, you need to exercise it. How do you do it? By being active in a way that gets you huffing and puffing, like jumping rope, dancing, or playing basketball. Try to be active every day!

* Eat a variety of healthy foods and avoid foods high in unhealthy fats, such as saturated fats and trans fats.

* Remember smoking can damage the heart and blood vessels. Even if you don't smoke, being around those who smoke can be harmful. You become a passive smoker then.

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