In this issue:
Have you ever heard your heart? How about someone else's heart? Doctors use an instrument called a stethoscope to listen to your heartbeat. In this experiment, you can listen to your heartbeat with a stethoscope like doctors use, or make your own simple stethoscope.
Exercise makes our heart beat faster. When our bodies are working harder, we need a steady blood supply. Our hearts provide blood to all parts of the body, even our brains! When we exercise, it also exercises the heart! Our hearts have to work a lot harder to pump blood while we are exercising. Our blood contains oxygen, which we need during exercise. As we use up the oxygen that our blood supplies, our heart has to keep pumping new blood into our system. Even after you were done exercising, your heartbeat was still faster than normal. This is because as your body cools down, you still need a strong oxygen supply. You can try the experiment again with less exercise (5 minutes) or more exercise (30 minutes). What are some times when your heart beat really fast? Why do you think that is? Sometimes something scary like riding a rollercoaster will make our hearts beat fast.
Doctor: Nurse, did you take the patient's pulse?
Nurse: No, why? Is it missing?
Question: Why did the skeleton fail the test?
Answer: His heart wasn't in it.
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Human hearts have four chambers and work as a pump delivering blood to your body. Deoxygenated blood—which needs a fresh supply of oxygen—is brought by veins in from the body into the first chamber, known as the right atrium. The heart them pumps the blood into the right ventricle, and from there it is pumped to the lungs. In the lungs, the blood receives oxygen. From the lungs, the oxygenated blood is brought back to the heart. The blood passes through the left atrium into the left ventricle, and from there it is pumped through your arteries to the rest of the body. Check out our heart worksheet to test your knowledge of the five basic parts of the heart.
The largest artery in the body is the aorta and it's located above the left ventricle. This process of moving blood through the body is called circulation and it repeats itself all day, every day throughout your life! When you were exercising, you needed more oxygenated blood, so your heart had to work harder! That's why it beat faster after exercise. The sound of your heartbeat is the sound of valves in your heart closing. Valves act like doors in your heart, controlling how much blood goes in and out.
Blood's circulation path: body >> veins > > right atrium > > right ventricle >> lungs >> left atrium >> left ventricle >> arteries >> body
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