There are over 650 muscles in the human body. They are under our skin and cover our bones. Muscles often work together to help us move. We don't really have to think about moving each individual muscle. For example, we just think of running and our body does the rest.
How Muscles Work
Muscles work by expanding and contracting. Muscles have long, thin cells that are grouped into bundles. When a muscle fiber gets a signal from its nerve, proteins and chemicals release energy to either contract the muscle or relax it. When the muscle contracts, this pulls the bones it's connected to closer together.
Many of our muscles come in pairs. An example of this is the biceps and triceps in our arms. When the biceps contract the triceps will relax, this allows our arm to bend. When we want to straighten our arm back out, the biceps will relax and the triceps will contract. Muscle pairs allow us to move back and forth.
Tendons connect muscles to bones. Tendons help form a connection between soft contracting muscle cells to hard bone cells.
When we practice an action over and over again, we get what is called muscle memory. It allows us to become more skilled at certain activities such as sports and music. As we practice, our muscles tune themselves to become more precise in their motions and to do exactly what our brain wants them to do. So remember, practice makes perfect!
Muscles and Exercise
When we exercise we work our muscles allowing them to become bigger and stronger. Exercise helps keep your muscles strong and flexible. If you don't use your muscles they can atrophy, or shrink and become weak.
Fun Facts about Muscles
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