Muscular System

The muscular system is made up of over 600 muscles.  But we are going to discus main 5 muscles:

  • main functions of the muscular system,
  • the 5 major properties
  • the 5 types of muscle movements
  • 3 types of muscles
  • and how all of this works together to make up the muscular system.

The primary purpose for the Muscular system is to provide movement for the body.  The muscles receive their ability to move the body through the nervous system.

Major Properties of the Muscular Systemmuscular system

There are 5 major properties to the muscular system

    1. Excitable or Irritable:  Muscles are Excitable or Irritable. This means that they are capable of receiving stimulation and responding to stimulation from the nerves.
    2. Contractible:  They are contractible. After receiving stimulation, they are capable of contracting, or shortening.
    3. Extensible: Being extensible means a muscle can be stretched without damage by the application of force.
    4. Elasticity: With elasticity, a muscle is able to return to its original resting shape and length after being extended or contracted.
    5. Adaptability: The muscular system is adaptable in that it can be changed in response to how it is used. For example, a muscle will enlarge, or undergo hypertrophy with increased work; but on the other hand it can go in  atrophy, or waste away if deprived of work.


Types of Muscle Movements

Now, lets look at the 5 types of muscle movements.

  1. Adduction…is the moving of a body part toward the mid-line of the body.
  2. Abduction…is moving a body part away from the body.
  3. Flexion…Flexion means bending a joint to decrease the angle between two bones or two body parts.
  4. Extension…extension is straightening and extending of the joint to increase the angle between two bones or body parts.
  5. Rotation… and last, rotation involves move a body part around an axis.


3 Types of Muscles

The Muscular System is divided into three main types. Each of these types can be moved 1 of 2 ways. either voluntary, or involuntary.  Cardiac Muscular System

  1. Cardiac Muscle – The cardiac muscle, is an involuntary muscle; meaning it operates without any conscious control.
  2. The Visceral or smooth muscles, are also considered involuntary – these muscles are found in organs or organs systems such as the digestive or respiratory system.
  3. The third type of muscle is the Skeletal muscle. These are what we would typically think of when talking about muscles.  These muscles attach to the skeleton and provide the skeleton with the ability to move. The Skeletal Muscles are classified as voluntary. This is because we have to make a conscious effort or decision to make them move.


Supportive Structures

Although muscles obviously make up muscle system, there are still some supportive structures we need to look at that are also a necessary part of the system. Tendons and fascia are important supportive structures for the Skeletal muscles.

Simply put,Tendons are what attach a muscle to a bone. Fasciae connect muscles to other muscles. Tendons and Fascia work together with the muscles, which creates the muscular system necessary for movement.


muscular system

The Nervous System

While not technically part of the same system, the nervous system is intrinsically connected to the muscular system of the body. It is essential to the voluntary skeletal muscles.

If the communication from the nervous system is severed from the skeletal muscles, the skeletal muscles will not be able to produce movement for the body. The body is now in a state of paralysis.  This is known as  quadriplegia.  The only organ that is not directly dependent upon the nervous system is the Cardiac (heart) muscle.



There are 5 major properties to the muscular system.

  1. Excitable or Irritable
  2. Contractible
  3. Extensible
  4.  Elasticity
  5.  Adaptability

There are 5 types of muscle movements.

  • Adduction…
  • Abduction…
  • Flexion…
  • Extension…
  • Rotation…


There are 3 Types of Muscles; voluntary and involuntary

  • Cardiac Muscle – involuntary
  • The Visceral or smooth muscles – involuntary
  •  Skeletal muscle – voluntary


Supportive Structures

Tendons and fascia are important supportive structures for the Skeletal muscles.

The Nervous System is intrinsically connected to the muscular system of the body. It is essential to the voluntary skeletal muscles…


This was the summary of Lesson 3 ( Muscular System).