Muscular System

Human anatomy > Muscular System

Without the muscles to fill in those spaces in the skeletal system, imagine how a human body would look like. The muscular system consists of 639 muscles that can flex, contract and stretch to perform a variety of body movements. These movements can be voluntary and involuntary. The voluntary movements are those that you can control consciously, while the involuntary are movements that you cannot control. Muscle contractions cause these body movements and occur when actin and myosin filaments slide over each other. 

Muscular System

The Major Functions of the Muscular System are the following:

  • Responsible for coordinated body movements. If the skeletal system is the foundation, the muscular system makes the actual movements through the relaxation and contraction of the muscles.
  • Responsible for circulation through the contraction of the cardiac muscles. Through the cardiac muscles, the heart can supply blood to the different parts of the body. Without the cardiac muscles, circulation will not be possible.
  • Provides stability and posture to body.  You can thread a needle because your hands are steady because of the muscles in it.
  • Generates heat for the body through exercise, causing muscle contraction and relaxation.
  • Aids in digestion through the involuntary movement of the muscles involved in digestion, like the jaw muscle, which is the strongest muscle in the body.

General Types of Muscles

Smooth muscles - These fusiform, striated muscles are involuntary and can be found in the urinary bladder,  the gastrointestinal and urinary tracts, and the arteries and veins of the circulatory system.  

Cardiac muscles - The cardiac muscles are involuntary muscles characterized by striations and many mitochondria.  Normally, the myocardium does not tire easily.  Cardiac muscles are involuntary because they contract and relax without your conscious thought commanding them to. 

Skeletal muscles -These are muscles, usually voluntary and characterized by cells, which are multi-nucleated.  Skeletal muscles are found everywhere in the body, like the biceps found in the arms, the gastrocnemius found in the legs, and the trapezius, which originates from the vertebral column.

Conditions Associated with the Muscular System

Sprains or Strains

These are the most common causes of muscle injury.  Accidents like falling can result to a sprain, which is a torn or stretched ligament in your body.  These ligaments are responsible in attaching muscles to the bones. They can also result to a strain in which the muscles are involved.  The therapy can involve physical therapy and drugs, depending on the severity of the injury.

Muscular Dystrophy

It is a condition characterized by the death of muscle tissues because of the lack of proteins. This results to muscle weakness and muscle wasting.   Doctors manage the condition by conducting physical therapy and take measures to prevent complications, as there is no cure for muscle dystrophy.

Distal Muscular Dystrophy

This is a type of genetic muscular dystrophy. It involves the distal parts of the body, like the lower legs, the hands and forearms.  The symptoms may manifest during adulthood and progresses slowly. If your family has a history of this condition, then you can inherit it through your genes.


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