Muscles Study Guide


A muscle is made up of a group of muscular tissues that contract together and create a force. The muscles are composed of muscle cell fibers surrounded by a protective tissue bundled with many fibers, all of which are surrounded by a thick layer of protective tissue. A muscle contracts and shortens, which lets it force itself on objects it is connected to. There are many types of muscle that act together in various parts of the body.

Structure of the muscle

Let us now understand the muscle structure and the various types of muscle tissue!

  • A muscle comprises several muscle tissues bundled with each other and surrounded by an epimysium, like cartilage.
  • The epimysium surrounds many nerve cells that run across long fibers.
  • The fibers have their protective layer, which lets blood and nerves flow to the individual fibers. Another layer then protects these fibers.
  • The muscles in the human body are thus a pattern of bundled fibers separated into various protective layers. It is these bundles and layers that let different parts of the muscles contract.

Function of muscle

Every muscle in your body has a role to perform. Be it a small or a large muscle, each muscle is important. It could be a muscle that controls eye movement or a muscle that controls the movement of your arms and legs.

Every muscular tissue type, however, functions in the same way.

  1. A signal is first sent to the brain and a nerve bundle, and the chemical and electronic message is passed from one to the other nerve cell until it reaches the motor end plate.
  2. The nerve cells and the muscle interface release a chemical signal that tells the muscle fibers to contract.
  3. This message gets distributed to the cells in all the fibers that are connected to the nerve.

There are several uses of muscles, be it for swimming, flying, or running. Even the heart is a muscle that pumps blood throughout the body. These are the major functions of muscles.

Types of Muscle

Skeletal muscle

The skeletal muscles are the biceps, the triceps, and the quadriceps. This is the image that comes to mind when you think of muscles. The general muscles are made of small muscles attached in varied places to give full motion to the joint. The skeletal muscles are controlled by the somatic nervous system.

Visceral muscle

Visceral muscles are found in internal organs like the stomach, blood vessels, and intestines. It is an involuntary muscle because our conscious mind cannot control it.

Cardiac muscle

The cardiac muscle is like the skeletal muscle and is connected to our autonomous nervous system. This is the system that controls the body’s vital organs like the lungs and the heart.

Smooth muscle

The smooth muscles are unlike the cardiac and skeletal muscles, not striated. The individual cells of the muscles are not aligned with the sarcomeres perfectly. Instead, these are displaced through the fibers. Our autonomous nervous system controls the smooth muscles.


  • Muscles are a specialized part of the body that is responsible for locomotion and movement in animals.
  • These are composed mostly of the muscle tissues.
  • The animals, muscles are further divided into several types.
  • In total, the human body has approximately 650 skeletal muscles.


1. What is a muscle?

The muscles are the tissue in the body that consists of long cells which contract and produce motion. Muscles are made of a kind of elastic tissue.

2. What is a muscle in the human body?

The human body muscles are a kind of elastic tissue, responsible for ensuring posture, movement, and balance in the body. The muscles can be voluntary or involuntary.

3. What are the 14 muscles in the body?

  • Sternocleidomastoid
  • Pectoralis Major
  • Rectus Abdominis
  • Rectus Femoris
  • Sartorius
  • Trapezius
  • Deltoids
  • Triceps
  • Latissimus Dorsi
  • External Oblique
  • Gluteus Maximus
  • Hamstrings
  • Gastrocnemius
  • Biceps

4. Is your brain a muscle?

No, the brain is not a muscle.

5. What’s the strongest muscle in your body?

The masseter is the strongest muscle in the human body.

6. What are the 4 main functions of muscles?

  • Posture
  • Stability.
  • Digestion
  • Mobility

7. Which organ systems contain muscles?

The cardiac and digestive systems contain muscles.

We hope you enjoyed studying this lesson and learned something cool about the Muscles! Join our Discord community to get any questions you may have answered and to engage with other students just like you! We promise, it makes studying much more fun 😎


  1. Muscle Accessed Nov 26, 2021
  2. Muscle Accessed Nov 26, 2021
  3. 14 Muscles in the Human Body Accessed Nov 26, 2021

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