Our bodies move because our brain tells different parts of our body to do stuff and then our body listens.

But in order for our bodies to move with these instructions, our bodies must consist of certain features such as bones, joints and muscles.

These different features help our bodies to move and to do things that we do on a daily basis.

How Do Muscles Work?

If you tell your body to pick up a gallon of milk and hold it over your head, your body will do that, but how? Muscles help us to do things such as lifting, sitting and everyday things that you do.

One great thing about muscle function is that we do not have to tell our muscles to work, they just do.

Different Muscles

Your body has over 600 different muscles and most of these are called skeletal muscles. Skeletal muscles are muscles that are attached to the bones and these types of muscles help us to do voluntary movements, which are movement that we can control.

Skeletal Muscles

Skeletal muscles are attached to our bones and these are attached with tendons. Tendons are tissue that is strong, and it connects to the bones so that our bones can help the muscles to move.

One interesting fact about muscles is that they can only pull and not push, so oftentimes, muscles are forced to work in pairs in order to make our bodies to move correctly.

An example of this is your arm. In order to raise your forearm, your bicep muscle contracts and at the same time, your triceps muscles that are located on the back of your arm relaxes.

With this pair working together, the muscles help you raise your arms. Many other muscles work together in order to make movement happen.

Skeletal Muscles in the Face

Most skeletal muscles help to move our bones, but some skeletal muscles move parts of our face, such as our eyes.

There are many different muscles that work together to move your eyeball.

Because our eyes can move up, down, sideways and more, there are muscles that are attached to the top, bottom and side of the eyeball and the other end is attached to the bone in the eye socket.

Involuntary Muscles

These muscles in your eyes are involuntary muscles, and you will learn what involuntary means below.

Most of the time when we think of muscles, we think of ones that move our bones. There are other muscles that move other parts of your body.

Smooth Muscles

Muscles in the stomach and in the intestine have muscles called smooth muscles.

Smooth muscles are muscles that contract or move involuntarily such as when you swallow food and it moves through your digestive system.

Cardiac Muscles

Another type of muscle is a cardiac muscle. Cardiac muscles are located in your heart and these muscles contract so that blood can pump through the heart.

The cardiac muscles are also involuntary muscles.

Remember, voluntary muscles are ones that you control, and involuntary muscles are ones that your body does for you.

Your brain tells these muscles to move and your body is not even aware that your body is using these muscles.

Striated Muscles and Myofibrils

Sometimes, muscles are arranged in bundles. Muscles that are arranged in bundles are called striated (striped) muscles.

There are also threadlike structures that are found in the muscle fiber and these are called myofibrils. The basic functional unit of a muscle is called sarcomere.

Sliding Filament Theory

The explanation of how muscle fibers contract are called the Sliding Filament Theory.

The Sliding Filament Theory tells us how muscles can only move one way and how muscles work with actin and myosin to form a bridge movement that helps muscles contract.

Facts About Muscles:

  • Skeletal muscles are voluntary, striated muscles attached to bones that allow the body to move by contracting in short, strong bursts.
  • Smooth muscles are involuntary, not striated muscles that move food and other substances through the body, while helping the organs carry out their particular functions and they contract slowly but steadily.
  • The location of the smooth muscles are oftentimes found in lines inside of organs such as the intestines and the stomach.
  • Cardiac muscles are involuntary muscles that are striated, they are responsible for making the heartbeat, and electrical impulses are sent to the brain, causing all of the muscle fibers to contract at the same time.
  • Cardiac muscles are found only in the heart.
  • Some skeletal muscles are attached to the ends of bones and are found opposite of joints.
  • When a muscle contracts, the bone moves.
  • Exercise is needed to help keep muscles strong.
  • Muscles, which are made up of muscle fibers, contain hundreds of myofibrils, which are threadlike bundles of structure that are found in the muscle fibers.
  • Myofibrils are made up of sections of sarcomeres which are the basic functional unit of the muscle.
  • Each sarcomere has an actin and a myosin which are protein filaments.
  • Actin filaments and myosin filaments work together with what some call bridge structures to help the muscle contract. This is the Sliding Filament Theory, explaining how the actin and myosin help the muscle fibers to contract.

What Did You Learn?

  • There are over how many muscles in the human body? The body contains over 600 different muscles in the human body.
  • What type of muscles are attached to bones with tendons? Skeletal muscles are attached to bones with tendons. These muscles work voluntarily, meaning we think when we use these types of muscles.
  • What type of muscles are found in the stomach and the intestines, as well as in other parts of the body? Smooth muscles are found in the stomach and the intestines, as well as other parts of the body. The smooth muscles work involuntarily to help aid in organ functions. This means, that we use these muscles without thinking about it, our body does it on its own.
  • What type of muscle is found in the heart? The cardiac muscle is found in the heart. The cardiac muscle is an involuntary muscle that helps make sure the heart beats. We do not have to do anything to make our heart beat, therefore, this is an involuntary muscle.
  • Muscles that are arranged in bundles are called what? Striated muscles are muscles that are arranged in bundles.
  • What is the threadlike structure that is found in muscle fibers? Myofibrils are threadlike structures that are found in the muscle fibers.
  • What is used to explain the way that muscles contract? The Sliding Filament Theory helps to explain how muscles contract.