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Muscular System

Muscular System

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This lesson will introduce the structure and function of the bodies muscular system including the three types of muscle.

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Tutorial

What's Covered

This lesson will cover the muscular system, and the three main types of muscle found in the human body.

  1. Muscular System
  2. Cardiac Muscle
  3. Skeletal Muscle
  4. Smooth Muscle

1. Muscular System

There are a total of 11 body system, and the muscular system is one. The muscular system allows for movement, production of body heat, and the flow of blood and other substances.

The three main types of muscle found in our body are:

  • skeletal muscle
  • smooth muscle
  • cardiac muscle

Term to Know

    • Muscular system
    • One of the eleven organ systems of the human body; contains three different types of histologically different forms of muscle (smooth, cardiac, skeletal) that are found in different areas of the body but all share the same primary function and movement.

Muscles can be either:

  • voluntary
  • Involuntary

Voluntary muscles are a type of muscle that you have control over. Involuntary muscles are muscles that you do not have control over.

Think About It

Let’s take a look at two different muscles and decide if they are voluntary or involuntary:

Imagine flexing and extending your arm. Is this voluntary or involuntary?This is something you consciously have control over, so this would be a voluntary muscle.

Now, think of the muscles in your digestive tract that push food through your small and large intestine. Voluntary or involuntary? We do not have to consciously think about moving food we ingest through our system. Our body automatically does this, so this is involuntary.

Terms to Know

    • Voluntary muscle
    • Muscle that we have conscious control of; skeletal muscle is the only one of the three.
    • Involuntary muscle
    • Muscle that we have no conscious control of; cardiac and smooth muscle are in this category.

2. Cardiac Muscle

Cardiac muscle is the type of muscle that is found in our heart, and is a type of striated muscle. This means that it has a striped appearance. Look at the diagram below of what it might look like close up. Notice the little stripes that go through it because of the way that the cells are composed.

Types of muscle (2).png

Term to Know

    • Cardiac muscle
    • A form of muscle that contains short, branched, striated single nucleated cells; cardiac muscle is only located in the heart and is used to pump blood throughout the cardiovascular system.

Cardiac muscle is an involuntary muscle, and can contract without stimulation from the nervous system. The cells in cardiac muscle seem to contract as a single unit, however, they are not. A contraction moves through the cells so quickly that it's as if these cells are contracting as a single unit.


3. Skeletal Muscle

The majority of muscles in your body are skeletal muscles, and they work in conjunction with your skeletal system. They help to stabilize the joints, they allow for movement of our body, and they allow for us to produce body heat.

Term to Know

    • Skeletal muscle
    • A form of muscle that contains very long, striated, multinucleated cells; skeletal muscles are the largest form of muscles in the body and attached to the skeleton; these are used for the movement of our bones, generate heat and protect deeper internal organs.

The image below is the bicep muscle. It's working with your skeleton in order for your skeleton to be able to move in the way that you want. Skeletal muscles are long thin cells made up of more than one nucleus, referred to as fibers, and these fibers are arranged into bundles. The bundles are arranged in a way that looks like they have this stripe look, which is called striated muscle, similar to cardiac muscle.

Types of muscle (3).png

And skeletal muscle is a type of voluntary muscle; you have concsious control over these muscles.


4. Smooth Muscle

Smooth muscle composes the walls of hollow organs and tubes like our blood vessels or digestive tract. The name describes the appearance of this type of muscle; It doesn't have a striped appearance, like cardiac and skeletal muscle.

Term to Know

  • Smooth muscle
  • A form of muscle that contains short, tube-like (fusiform) single nucleated cells; smooth muscle range from having many layers to a single layer of cells; smooth muscle is found in the walls of hollow organs.

The cells of smooth muscle are also generally a little bit smaller, and are organized into sheets. Smooth muscle is another type of involuntary muscle. Look at this picture of a blood vessel:

Types of muscle (4).png

The inside of this blood vessel would be lined with smooth muscle, which helps to contract and push blood through. This happens on its own with input from your nervous system.

Summary

The muscular system is one of 11 body systems, and is responsible for allowing movement, production of body heat, and the flow of blood and other substances throughout your body. Muscles can be voluntary or involuntary. The cardiac muscle is the type of muscle found in your heart. It is an involuntary muscle with a striated appearance. Skeletal muscle works with your skeletal system to allow for movement, and is the only voluntary muscle of the three different types. It also has a striated appearance. Smooth muscle is the last type of muscle. It is smooth in appearance and involuntary. It lines the walls of hollow organs and tubes in our bodies.

Keep up the learning and have a great day!

Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

TERMS TO KNOW
  • Muscular system

    ​One of the eleven organ systems of the human body; contains three different types of histologically different forms of muscle (smooth, cardiac, skeletal) that are found in different areas of the body but all share the same primary function and movement.

  • Skeletal muscle

    ​A form of muscle that contains very long, striated, multinucleated cells; skeletal muscles are the largest form of muscles in the body and attached to the skeleton; these are used for the movement of our bones, generate heat and protect deeper internal organs.

  • Cardiac muscle

    ​A form of muscle that contains short, branched, striated single nucleated cells; cardiac muscle is only located in the heart and is used to pump blood throughout the cardiovascular system.

  • Smooth muscle

    ​A form of muscle that contains short, tube-like (fusiform) single nucleated cells; smooth muscle range from having many layers to a single layer of cells; smooth muscle is found in the walls of hollow organs.

  • Voluntary muscle

    Muscle that we have conscious control of; skeletal muscle is the only one of the three.

  • Involuntary muscle

    Muscle that we have no conscious control of; cardiac and smooth muscle are in this category.