How do muscles help in movement?Explain in detail.
Answers
Muscles pull on the joints, allowing us to move. They also help the body do such things as chewing food and then moving it through the digestive system.
Even when we sit perfectly still, muscles throughout the body are constantly moving. Muscles help the heart beat, the chest rise and fall during breathing, and blood vessels regulate the pressure and flow of blood. When we smile and talk, muscles help us communicate, and when we exercise, they help us stay physically fit and healthy.
Humans have three different kinds of muscle:
Skeletal muscle is attached by cord-like tendons to bone, such as in the legs, arms, and face. Skeletal muscles are called striated (pronounced: STRY-ay-ted) because they are made up of fibers that have horizontal stripes when viewed under a microscope. These muscles help hold the skeleton together, give the body shape, and help it with everyday movements (known as voluntary muscles because you can control their movement). They can contract (shorten or tighten) quickly and powerfully, but they tire easily.
Smooth, or involuntary, muscle is also made of fibers, but this type of muscle looks smooth, not striated. We can't consciously control our smooth muscles; rather, they're controlled by the nervous system automatically (which is why they're also called involuntary). Examples of smooth muscles are the walls of the stomach and intestines, which help break up food and move it through the digestive system. Smooth muscle is also found in the walls of blood vessels, where it squeezes the stream of blood flowing through the vessels to help maintain blood pressure. Smooth muscles take longer to contract than skeletal muscles do, but they can stay contracted for a long time because they don't tire easily.
Cardiac muscle is found in the heart. The walls of the heart's chambers are composed almost entirely of muscle fibers. Cardiac muscle is also an involuntary type of muscle. Its rhythmic, powerful contractions force blood out of the heart as it beats.
Answer:
Some muscles in our bodies are attached to bones, and when they contract, the bones move. That’s how you can eat delicious food…just lifting food from your plate, to your mouth, requires your ‘bicep’ to contract.
‘Contract’ means the muscle fibres (the stuff that makes up the muscle) stack up and become shorter. When the bicep shortens, it lifts your hand towards your face!
Every time a muscle contracts, another muscle relaxes. In the case of your biceps, it’s the tricep that relaxes when you bring food from the plate to your mouth. They work together in pairs!! They’re a great team, just like you and your friends are.
Muscles contract and relax
So for me to eat my healthy food, which fuels my movement, my brain has to send a signal down to my arm, telling the bicep to ‘contract’ (shorten), and the tricep to ‘relax’ (lengthen). Clever brain!!
Have a go with this action, to help you understand:
Look at a partner’s arm when they pretend to eat something, can you see their bicep contract, and their tricep relax?
You can strengthen your biceps and triceps by doing pulling and pushing movements. Give this a go…
Stand behind your chair, then squat down to pick it up safely. Now, standing with long arms, holding onto your chair, bend your elbows to lift your chair up, and then lower it down again. When you do this, keep your tummy gently ‘pulled in and up’, and your knees bent. Do this five times…you’ve just pulled the chair towards you using your biceps!
To use your triceps, sit on the chair with your hands holding onto the seat, just under your legs. Scoot your bottom off the chair, so you are still holing on with your hands, but your bottom is just in front of the chair. Now bend your elbows and lower yourself down, then push up again by straightening your elbows. Do this five times…you’ve just pushed yourself up using your triceps!
Do you know the names of any other muscles in the body? What actions can you do to make them contract? Which muscle has to relax in order for that one to contract?
Our heart is a muscle as well…does that means it contracts too? Find out what you can and tell us about it below!
hope it will help you
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