Muscular System – Main Functions, Interesting Facts, Types, Diseases

Interesting Facts

The parts of muscle include the tendon, which is a fibrous connective tissue attaching that muscle to the bone; the muscle material itself; and the ligament, which connects nearby bone to bone for stability.

There are more than 650 skeletal muscles, and that number doesn’t include the smooth muscles. Smooth muscles are controlled by the autonomic nervous system. This means that they are incapable of being moved by our will.

It takes you about 30 days to develop a muscle, and it will take approximately 60 days for that muscle to reach its original size and strength. The fleshy, triangular-shaped muscles which form the rounded shape of the shoulders are the deltoid.

The muscles in your heart function continuously, from the moment you are born until the day you die.

The smallest muscles are found in the middle ear. Some of these are the Stapedius and the tensor tympani (connected to the eardrum). The muscle which lets your eye blink is the fastest muscle in the human body. It allows you to blink 300 times per minute.

About 85 percent of the human body heat is generated by muscle contractions since your muscle fibers are working to heat up your body temperature.

The muscles of the face are unique due to the fact that they are attached to the skin or other muscles on one end and the skull on the other end. Irritability is the muscles’ capacity to respond to stimulus whether the response is severe, like – muscle damage, tearing, or breakdown, or basic, like – movement.

Muscles make around 40 percent of your total body weight. When you smile, you are using 17 muscles. For every step you take during the day, you are actually exercising about 200 muscles at the same time. The longest muscle is the Sartorius. It helps us bend the knee and twist our leg and runs from the hip to the knee.

What Is The Main Function Of The Muscle System?

The main function of this system is movement since they are the only tissue in the human body that has the capacity to contract, hence, to move the other parts of the body. Other functions include:

  • the smooth muscles of the intestines and stomach work to process the food we consume.
  • cardiac muscle (found in the heart) is an involuntary muscle responsible for pumping blood throughout the human body. Cardiac and visceral muscle tissues surround the lymph vessels and blood vessels which carry vital nutrients to the cells of the body.
  • the urinary and digestive tracts are surrounded by skeletal muscles. These muscles provide voluntary control over defecation, swallowing, and urination.
  • muscles play essential roles in providing stability and balance, maintaining posture, and even keeping the body temperature normal.


Skeletal Muscles

They are attached to the bone and help you with day-to-day activities, ranging from standing and sitting to typing, walking, running, and doing housework. These muscles are voluntary since we control them directly with signals from the brain.

This type of muscle is made of long cylinder-shaped cells (muscle fibers), that have numerous nuclei within each cell. This fiber is excited by myelinated nerve fibers that attach to the myoneural junction.

Cardiac Muscles

They are involuntary since they are not under the control of our will. They contract non-stop throughout life to pump blood from the heart to the lungs and around the human body. The cells of cardiac muscle tissue are striated. This is the main reason they appear to have dark and light stripes when observed under a light microscope.

Smooth Muscles

Their contractions are involuntary movements triggered by impulses that travel through the autonomic nervous system to the smooth muscle tissue. This type of muscle is found in internal organs, including – blood vessels, digestive system, respiratory organs, bladder (they allow you to hold in urine until you can get to the bathroom), and the uterus (only for females).

They contract to move substances, like – food through the organ.


Smooth and cardiac muscles are fatigue resistant, as opposed to skeletal muscle that fatigues relatively easily.


Some of the most common disorders of the muscular system include:

Myasthenia Gravis – it is a chronic autoimmune disease, where muscle fatigue and weakness are caused by the breakdown of the neuromuscular junction. There is no cure for this condition, but treatment can help reduce the symptoms and signs.

Myotonia – it is a medical problem in which the muscles relax slowly after stimulation or contraction. Specific signs and symptoms of this disorder include – trouble walking, trouble releasing a grip on a particular object (like – a spoon or a cup), and problems getting up from a chair or bed.

Muscular dystrophy – it is actually a group of genetic diseases, characterized by progressive degeneration of skeletal muscles, which are the muscles that control movement.

Duchenne’s muscular dystrophy – it is described by increasing muscle weakness.

Images credit – Shutterstock

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