Question of the Week
February 14, 2005


It's that time of year. Hearts are everywhere: heart candy, heart cards, heart decorations at the mall (or even at school).

"A long time ago, people even thought that their emotions came from their hearts, maybe because the heart beats faster when a person is scared or excited. Now we know that emotions come from the brain, and that the brain tells the heart what to do. So what's the heart up to, then?"

"So what's the heart up to, then?"

Let's start with the basics:

"...Your heart is sort of 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 left side of the heart does the exact opposite: It receives blood from the lungs and pumps it out to the body. ... Before each beat, your heart fills with blood. Then its muscle contracts to squirt the blood along. When the heart contracts, it squeezes - try squeezing your hand into a fist. That's sort of like what your heart does so it can squirt out the blood. Your heart does this all day and all night, all the time. Every day, an adult heart pumps 2,000 gallons (7,500 liters) worth of blood by filling and contracting - and sending the blood around and around again.

It has been said that a picture is worth a thousand words.... To see a simple, clear animation of the heart valves at work, visit:

If you want to see more, you can see another animation that shows the blood flowing to and from the heart at:

So you have the basics, but what if you want, or need, to know more?

"Blood is pumped through the chambers, aided by four heart valves. The valves open and close to let the blood flow inonly one direction. ... Dark bluish blood, low in oxygen, flows back to the heart after circulating through the body. It returns to the heart through veins and enters the right atrium. This chamber empties blood through the tricuspid valve into the right ventricle. The right ventricle pumps the blood under low pressure through the pulmonary valve into the pulmonary artery. From there the blood goes to the lungs where it gets fresh oxygen. After the blood is refreshed with oxygen, it's bright red. Then it returns by the pulmonary veins to the left atrium. From there it passes through the mitral valve and enters the left ventricle. The left ventricle pumps the red oxygen-rich blood out through the aortic valve into the aorta. The aorta takes blood to the body's general circulation. The blood pressure in the left ventricle is the same as the pressure measured in the arm.

The animations above will offer a visual for that more detailed description of the heart, as well. But what if you need to know what the heart really looks like?

"This is the external appearance of a normal heart. The epicardial surface is smooth and glistening. The amount of epicardial fat is usual. The left anterior descending coronary artery extends down from the aortic root to the apex."

That image above is just one of 130 images of healthy and diseased hearts that you can find at:

So you have just seen the pictures of the hearts -- healthy and diseased. So what's next? What happens when a heart is having problems?

"Coronary bypass surgery involves replacing a diseased or constricted artery with a vein removed, most commonly, from the leg, where blood supply is plentiful. The surgeons
dissect the saphenous vein from the right groin area to the knee. The chest cavity is opened and the heart is elevated. Once the catheders are in place, the doctors begin suturing the new vessel to the heart, effectively repairing the affected blood flow. When the suturing is complete, the heart is given a slight electrical shock and resumes normal activity."

To see photographs that take you step by step through coronary bypass surgery, you can visit the link that accompanies the previous quote.

Sometimes the heart needs more than bypass surgery; it has been damaged so severely that it needs to be replaced.

"In this procedure the patient's heart is replaced with an artificial heart temporarily until a donor heart can be found. The doctors remove the heart and connect the patient to a heart-lung machine that artificially sustains blood flow and oxygenation. The artificial heart is surgically implanted into the chest cavity. When the patient is ready for transplantation of the donor heart, the artificial heart is removed and replaced with the human heart."

To see photographs that take you step by step through heart replacement surgery, you can visit the link that accompanies the previous quote.

Pictures of hearts are everywhere this time of year. There are those with lace, those made of chocolate, and those that remind you that February is Heart Health Month. Maybe you know the basics about how your heart really works and really looks. Maybe you know the specifics....

Questions of the Week:
As a student, what do you need to know about how your heart really works and looks? What members of society should know more about this than you do? Why? Is there anyone who doesn't need to know as much as you do? As a student (or an adult out of school), why is it important to know how the heart works? In what ways can knowing the biology of how the heart works help you make healthy (or healthier) choices? In what ways does this information not affect your decisions?

How do the written descriptions of heart function help your understanding in different ways than the images and animations? In what instances would you choose images rather than words? When would words be more helpful? When would you want both?

Please email me with any ideas or suggestions.
Note: Due to increasing amounts of SPAM sent to this account, please include "QOW" in the subject line when sending me email.

I look forward to reading what you have to say.

Health Community Coordinator
Access Excellence @ the National Health Museum

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