|
Robert Krampf's Experiment of the Week |
|
|
|
This Week's Experiment - #190 Have a Heart |
|
|
|
The idea for this week's experiment came to me while I was moving our stuff |
|
into the hotel where we will be staying for the next 3 weeks. The room is on |
|
the second floor and we do not travel light. Basically we take everything |
|
except the kitchen sink. We would probably take that as well, but it is too |
|
hard to disconnect. After the 14th trip up the stairs, I started to think |
|
about muscles and how they get tired. One thing lead to another, and soon I |
|
had this week's experiment written. Why do your muscles get tired? And more |
|
important, why does your heart, which is also a muscle, not get tired? To |
|
find out, you will need: |
|
|
|
you |
|
|
|
Your heart is a group of muscles which pump the blood through your body. To |
|
get an idea of its size, make a fist. That is about the same size as your |
|
heart. Pretending for a minute that your fist is your heart, lets take the |
|
idea a little farther. Open you hand about half way and then close it again. |
|
If you do that over and over, you can imagine that it is your heart beating. |
|
You can even make heart sounds (bump-bump) if you (bump-bump) want to. |
|
(bump-bump) |
|
|
|
Keep this pretend heart beating as you read this. Soon your hand will begin |
|
to get tired. If you keep opening and closing your hand even after you are |
|
tired, it will begin to hurt. Why? |
|
|
|
When you move your muscles, a chemical reaction takes place. Normally, this |
|
chemical reaction needs oxygen. We get this oxygen when we breath. The air |
|
moves into your lungs and the oxygen is absorbed by your blood. Your blood |
|
carries the oxygen to your muscles. As long as the muscle has plenty of |
|
oxygen, everything is fine and it can keep on moving. |
|
|
|
If the muscle uses up oxygen faster than the blood can deliver it, then what |
|
happens? The muscle does not instantly shut down when the oxygen runs out. |
|
Instead, a different chemical reaction takes over. It lets your muscles move |
|
even if they do not have enough oxygen. The problem with this backup system |
|
is that the reaction makes a chemical called lactic acid. This acid |
|
irritates the muscle, making it hurt. If you overdo it, your muscles will be |
|
sore the next day. Keep overdoing it and you can damage the muscle. |
|
|
|
If your heart is made of muscle, why doesn't it get tired? After all, your |
|
heart beats all day and all night, for your entire life. A large part of the |
|
answer has to do with blood. Your heart is between your lungs. Blood picks |
|
up oxygen from the lungs and flows directly to the heart. This insures that |
|
the heart always has plenty of oxygen, so it does not get tired. The one |
|
exception is if the blood vessels that lead to your heart get blocked. Then |
|
the heart muscles run low on oxygen and get tired. The pain that you feel is |
|
what tells you that you are having a heart attack. |
|
|
|
Athletes exercise regularly to increase the blood flowing to their muscles. |
|
If the muscles get more blood, they get more oxygen. Then they can work |
|
harder and longer before they get tired. Right now, I could use some extra |
|
oxygen, so I could unload the rest of our stuff. Have a good week. |
|
|
|
**************************************** |
|
Get volume 1 of the Experiment of the Week postings in book form! To order, |
|
send $9.95, plus $3.00 postage and handling to: |
|
|
|
Robert Krampf |
|
PO Box 60982 |
|
Jacksonville, FL 32236-0982 |
|
|
|
Include your e-mail address and I will notify you when I get your order. |
|
|
|
*************************** |
|
|
|
If you would like to be on the list, just send me an e-mail at [email protected], asking to be added to the Experiment of the Week List. |
|
|
|
Check out our web site at: |
|
http://www.krampf.com |
|
|
|
From Robert Krampf's Science Education Company |
|
4850 A1A South |
|
St. Augustine, FL 32084 |
|
(904) 471-4578 |
|
|
|
|