Muscles in your body

Did you know… … You have more than 600 muscles in your body! … They do everything from pumping blood through your body to helping you lift heavy weights. … You can control most of your muscles. But some do their jobs without you thinking about them at all.

What are muscles made of? Muscles are all made of the same material, a type of elastic tissue. Tens of thousands, of small fibers make up each muscle.

How many types of muscles do we have? You have 3 different types of muscles in your body: smooth muscle,  cardiac (KAR-dee-ak) muscle, and skeletal (SKEL-uh-tul) muscle.

Smooth muscles Smooth muscles are usually in sheets, or layers, with one layer behind the other. You can't control this type of muscle. Your brain tells these muscles what to do without you even thinking about it. Smooth muscles are at work all over your body. E.g. they are in your stomach and digestive system, they tighten and relax to allow food to make its journey through the body. They are in your bladder, they help your bladder hold on until you get to the bathroom.

Cardiac muscles The muscle that makes up the heart is a cardiac muscle. The thick muscles of the heart contract to pump blood out and then relax to let blood back in after it has circulated through the body. Just like smooth muscle, cardiac muscle works all by itself. A special group of cells within the heart are known as the pacemaker of the heart because it controls your heartbeat.

Skeletal muscles Skeletal muscles are voluntary muscles, which means you can control what they do. The skeletal muscles work with your bones to give your body power and strength. These muscles are some of the strongest, like the muscles in your neck and biceps.

Source: http://kidshealth.org/en/kids/muscles.html#