Muscle

What Are Muscles?

Muscles are special parts of our bodies that help us move. They are soft and stretchy, and they work like tiny helpers inside you. When you lift your arm, jump, or even blink, muscles are doing the work. There are three main kinds of muscles in vertebrates, which are animals with backbones, like humans.

Types of Muscles

One type is called skeletal muscle. These muscles are attached to your bones by strong bands called tendons. When you decide to move, like raising your hand, skeletal muscles make it happen. They look striped when you look at them very closely.

Another type is cardiac muscle. This muscle is only found in your heart. It works all the time to pump blood around your body. You don’t have to think about it; it just keeps beating.

The third type is smooth muscle. You find this in places like your stomach and intestines. Smooth muscle helps food move through your body and also works in your blood vessels. Like the heart, it works without you thinking about it.

Fun Facts About Muscles

The word “muscle” comes from an old word for mouse. People long ago noticed that some muscles look a little like a tiny mouse when they bend. Muscles are made of long cells called muscle fibers. Inside these cells are special things called actin and myosin that help muscles get shorter and longer, which makes movement possible.