The heart is a muscle in the body. The heart is divided into four parts. These parts are called chambers.
The job of each chamber is to pump blood to the organs of the body. The chambers of the heart are hollow so they can fill up with blood as it passes through each one.
This means the heart does not weigh very much, but without the heart, the body cannot live.
The four chambers or compartments of the heart are Left Ventricle, Right Ventricle, Left Atrium, Right Atrium.
How big is your heart
Like the other organs in your body, your heart grows with the rest of your body. The heart is always about the size of your fist. This means that when you were born, your heart was about the size of your tiny baby fist, and will stop growing when you do.
How does the heart work
There are two different kinds of ‘tubes’ coming off the heart that carry the blood from the heart to every part of the body. The two types of tubes are called veins and arteries.
Arteries carry blood away from the heart and veins bring blood back to the heart. This process is called circulation.
Circulation starts in the left ventricle of the t. The blood is pumped from there into the aorta, which is the largest artery in the human body. When it enters the aorta, the blood is filled with oxygen. The oxygen in the blood goes to every part of the body. Blood also carries hormones and other important nutrients and disease-fighting cells throughout the body.
While the blood is spreading oxygen and all those other things through the body, it is also picking up things we don’t need—things like carbon dioxide. When the blood has gotten rid of the oxygen and other important things, it comes back to the heart—going into the right atrium. From there, the blood goes into the right ventricle. The right ventricle has an important job. It sends the blood into the lungs so it can be refueled with more oxygen. When this has happened, the lungs send the blood to the left atrium and the whole process starts all over again.
How long does it take for the blood to travel through the body?
It takes about 20 seconds for blood to travel throughout the body. That is pretty amazing because if you stretched out all the veins, arteries, capillaries, and vessels the blood travels through, you would have a ‘rope’ 60,000 miles long! That’s long enough to circle the earth…twice!!!
But wait! Your heart beats more than every 20 seconds, so what’s up with that?
What is your heart rate?
It takes 20 seconds for blood to travel throughout your body. But your heart beats faster and more often than every 20 seconds because not all your blood goes through your body at one time. This means your heart is always pumping blood.
Have you ever noticed that sometimes your heart beats faster than it does at other times? Why is that?
How fast does your heartbeat
Here is what you need:
- Pen and paper
- The help of an adult
- Stopwatch, timer with seconds, or a clock with a second hand
Here is what you do:
Get familiar with checking your heart rate
To check your heart rate put your first two fingers over just below your jaw; pressing GENTLY and feeling for the spot where you can feel your pulse. If you are having trouble, ask a parent to help you.
Once you are confident you can check your pulse (heart rate) or have someone to do it for you, continue with the remaining steps in this experiment.
- Standing still, take your heart rate and write down the number of beats per minute
- Run in place for one minute, stop, take your heart rate and write down the number of beats per minute
- Lay down for one minute, take your heart rate and write down the number of beats per minute
- Walk around your house at a normal pace for one minute, take your heart rate and write down the number of beats per minute
- Look at the results—when did your heartbeat the fastest
- When did it beat the slowest
- What was your highest heart rate?
- What was your slowest heart rate?
Here is what happened:
The faster your body moves the more oxygen it takes for your body to function. This means your blood has to work harder and faster to get your body the oxygen it needs. So…to get it there faster, the heart has to pump faster—just like a car speeds up when you give it more gas.