Here is a Quizlet on muscles.
Did you know you have more than 600 muscles in your body? They do everything from pumping blood throughout your body to helping you lift your heavy backpack. You control some of your muscles, while others — like your heart — do their jobs without you thinking about them at all.
Muscles are all made of the same material, a type of elastic tissue (sort of like the material in a rubber band). Thousands, or even tens of thousands, of small fibers make up each muscle.
You have three different types of muscles in your body: smoothmuscle, cardiac (say: KAR-dee-ak) muscle, and skeletal (say: SKEL-uh-tul) muscle.
Smooth Muscles
Smooth muscles — sometimes also called involuntary muscles — are usually in sheets, or layers, with one layer of muscle behind the other. You can't control this type of muscle. Your brain and body tell these muscles what to do without you even thinking about it. You can't use your smooth muscles to make a muscle in your arm or jump into the air.
But smooth muscles are at work all over your body. In your stomach and digestive system, they contract (tighten up) and relax to allow food to make its journey through the body. Your smooth muscles come in handy if you're sick and you need to throw up. The muscles push the food back out of the stomach so it comes up through the esophagus (say: ih-SAH-fuh-gus) and out of the mouth.
Smooth muscles are also found in your bladder. When they're relaxed, they allow you to hold in urine (pee) until you can get to the bathroom. Then they contract so that you can push the urine out. You'll find smooth muscles at work behind the scenes in your eyes, too. These muscles keep the eyes focused.
Cardiac Muscle -The muscle that makes up the heart is called cardiac muscle. It is also known as the myocardium (say: my-uh-KAR-dee-um). 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 with no help from you. A special group of cells within the heart are known as the pacemaker of the heart because it controls the heartbeat.
Skeletal Muscle
Skeletal Muscles -Now, let's talk about the kind of muscle you think of when we say "muscle" — the ones that show how strong you are and let you boot a soccer ball into the goal. These are your skeletal muscles — sometimes called striated (say: STRY-ay-tud) musclebecause the light and dark parts of the muscle fibers make them look striped (striated is a fancy word meaning striped).
Skeletal muscles are voluntary muscles, which means you can control what they do. Your leg won't bend to kick the soccer ball unless you want it to. These muscles help to make up the musculoskeletal (say: mus-kyuh-low-SKEL-uh-tul) system — the combination of your muscles and your skeleton, or bones.
Together, the skeletal muscles work with your bones to give your body power and strength.
Skeletal muscles come in many different sizes and shapes to allow them to do many types of jobs. Some of your biggest and most powerful muscles are in your back, near your spine. These muscles help keep you upright and standing tall.
They also give your body the power it needs to lift and push things. Muscles in your neck and the top part of your back aren't as large, but they are capable of some pretty amazing things: Try rotating your head around, back and forth, and up and down to feel the power of the muscles in your neck. These muscles also hold your head high.
Try this web site and test your knowledge on muscles
