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health Lifestyle
Transcript
00:00Did you know that there are over 600 muscles in the human body?
00:12Muscles are an important part of your musculoskeletal system.
00:17They work with your bones and lots of other tissues so that you can move and live.
00:24Sitting under your skin and covering your bones, muscles do everything from pumping
00:29blood around your body to allowing you to smile and lift your backpack.
00:35We control some of our muscles while others, like those that make up our heart, do their
00:42jobs without us thinking about them at all.
00:48So how do muscles actually work?
00:51Muscles like those in our arms and legs work by contracting and relaxing.
00:57When the muscle contracts, this pulls the bones it's connected to.
01:03Many of our muscles work in pairs, like the biceps and triceps in your arms.
01:09When biceps contract, the triceps relax, which allows your arm to bend.
01:15When you want to straighten out your arm, the biceps relax and the triceps contract.
01:23Muscles work together to help you move.
01:27Big muscles pull big bones, like our arms and legs, so that you can walk, run, and lift.
01:35Smaller muscles and bones help with smaller movements, like shouting or tying your shoelaces.
01:42The muscles around your spine help you stand up straight and bend and to twist.
01:50What are muscles made from?
01:52Muscles are all made of the same material, a type of elastic tissue.
01:57Thousands of tiny fibers make up each muscle.
02:01And inside the muscles, there are nerves that carry messages to and from the brain.
02:07There are also blood vessels, which carry the energy that your muscles need to do their work.
02:14Skeletal muscles are the muscles we use to move around.
02:18They cover our skeleton and move our bones.
02:22You control these muscles with signals from your brain.
02:27Smooth muscles are special muscles that don't connect to bones, but instead control organs
02:33in your body.
02:34For example, you don't have to think about your stomach digesting your food.
02:39It does it all by itself.
02:43Cardiac muscles are very important muscles.
02:46They help your heart pump blood around your body.
02:50So how do you keep this incredible system of muscles healthy?
02:54Muscles grow and change throughout your life.
02:57When you exercise, you work your muscles, and they grow and become stronger.
03:04If you don't use your muscles, they can become weak, and that makes it hard to be active.
03:10But remember, to grow strong, healthy muscles, you don't need to lift weights.
03:16In fact, lifting weights before you are fully grown can damage your body.
03:21Instead, make physical activity a part of what you do every day.
03:26Play, climb, walk, join a team.
03:32Eating a healthy, well-balanced diet will also give your muscles energy and help make
03:37them powerful.
03:40Just like we couldn't survive without our bones, we can survive without our muscles.
03:46So look after them and keep them moving.