Muscles

MUSCLES

By Katrina Labonte

The body has three types of muscles; skeletal muscles (more than 600 all over the body), visceral muscles (stomach and intestines), and the cardiac muscle (the heart).  The largest muscle in your body is your buttock muscle.  The smallest muscle is in your ear.  Smiling only uses 17 muscles but frowning uses 43!  Try winking one eye at a time.  You have to think about this movement even though you blink with both eyes automatically hundreds of times a day.  This is because the brain has to learn how to use a muscle in a new and unfamiliar way. The heart (cardiac muscle) is a specialized involuntary muscle. It keeps its own rhythm and pumps life-giving blood around the body.  Every movement you make uses muscles.  They allow you to blink, jump, eat, run, and sing. 

Biceps and Triceps

by Sarah C. Bigam

Try this:

Hold your arm straight out in front of you with the palm of your hand facing up. With your other hand, feel the upper part of your arm, the part between your elbow and your shoulder. You can feel a muscle there. Make a fist with your right hand. Bring your fist up to your shoulder. You can feel the muscle in your upper arm change. It bunches up and gets harder. This muscles is called the biceps.

The top end of your biceps is fastened to a bone in your shoulder. The other end is fastened to a bone in your lower arm, just below your elbow. When your biceps bunches up and gets hard, we say it is contracting. It is drawing itself together. When it does this, it pulls on your lower arm, your elbow bends, and your fist comes up to your shoulder. Your biceps pulls your fist up to your shoulder. When you want to unbend your arm, you use another muscle. It is called a triceps.

Your triceps is on the back side of your upper arm. It also reaches from your shoulder bone down to a bone in your lower arm, just below the elbow. When your triceps contracts, it pulls your arm out straight again. Your biceps and triceps work together. First one pulls, then the other.

Many other muscles in your body work in pairs that way. They pull back and forth. By using your muscle, you can turn and twist your arms and wrists. By using your muscles, you can bend over and stand up straight, and do a lot of other things.