Difference WikiBiology

Difference Between Voluntary Muscles and Involuntary Muscles

Main Difference

The main difference between Voluntary Muscles and Involuntary Muscles is that Voluntary Muscles are in your control, whereas Involuntary muscles are not in your control.

Voluntary Muscles vs. Involuntary Muscles

The shape of voluntary muscles is in a long and cylindrical form. Involuntary muscles are tiny and fusiform. Voluntary muscles contain many nuclei in their cells. Involuntary contain only a single nucleus in their cells. Voluntary muscles experience fatigue and need rest after some time interval. Involuntary muscles can work continuously and don’t need rest and don’t fatigue. Voluntary muscles require a high amount of energy to perform a specific function. Involuntary muscles require less amount of energy to perform a function. Voluntary muscles are attached with the help of z-disk. Involuntary muscles are linked together by the intercalated disk.

Voluntary muscles show fast contraction and relaxation of muscles. Involuntary muscles show slow relaxation and contraction of muscles. Voluntary muscles are attached to the bones of our body. Involuntary muscles are found within the walls of the different body organs. Voluntary muscles are monitored by the individual’s will power. Involuntary muscles are not under the will power of an individual. Voluntary muscles help the different parts of the body for locomotion. Involuntary muscles help the different organs to perform different functions like breathing, digestion, etc.

Voluntary muscles are unbranched. Involuntary muscles have dwindled from the ends. Nuclei of voluntary muscles are present at the periphery of the muscle. Nuclei of involuntary muscles are present at the center of the muscle. Voluntary muscle possesses origin and insertion at the end of the muscle. Involuntary muscle doesn’t possess any origin and insertion at the end. Voluntary muscles exhibit strong contraction. Involuntary muscles exhibit rhythmically contraction.

Comparison Chart

Voluntary MusclesInvoluntary Muscles
Controlled muscles and you can choose them to perform work are voluntary musclesAutomatic muscles that work themselves without your control are involuntary muscles
Tissue Type
Striated stripped tissueNo stripes are found
Controlled By
Somatic nervous systemAutonomic nervous system
Type
Skeletal musclesSmooth muscles
Found In
Attached to our skeletonInternal organs e.g., heart, stomach, etc.
Sarcolemma
ThickThin
Work
Works at regular intervalsWorks continuously
Examples
Pharynx, muscles beneath the skin, muscles of the middle ear, diaphragm and abdominal wall of the tongue, etcRespiratory tract, duct glands, blood vessels, alimentary canal, and urogenital tract, etc

What are Voluntary Muscles?

Voluntary muscles are such a type of muscle that is regulated by the somatic nervous system as we know that these muscles are attached to the tendons or a bone, that’s why they are also said as skeletal muscles, which are being used mainly for the purpose of locomotion. Cells of voluntary muscles are multinucleated and cylindrical in shape. Every cell of the voluntary muscles is wrapped in the connective tissue and called “endomysium.” The cells of voluntary muscles are arranged in the form of the bundle, which then forms a functional tissue.

Every bundle of cells is wrapped by a connective tissue that is “epimysium’. When the bundle of cells gets wrapped, then they arranged in the compartments that are named “fasciculus.” Each fasciculus is again wrapped in the connective tissue called “perimysium.” The covering of connective tissue on the muscle is to provide them support or nourishment. Voluntary muscles possess about 40% of the total body weight. Voluntary muscles are regulated under the control of peripheral and central nervous systems.

Voluntary muscles are long and striped and found in the bundle of muscle fibers. These bundles of muscle fibers are bound by Sarcolemma, which further consists of sarcoplasm, uninucleated, which are found at the edges and sarcoplasmic reticulum. The dark and light bands are present in the muscles, which are known as myofibrils. These muscles play an important role in moving the body. These muscles are also necessary to maintain the posture of the body. Usually, these muscles work in an antagonistic manner.

What are Involuntary Muscles?

Involuntary muscles are those muscles that are not in our conscious control. Involuntary muscles categorized in the smooth muscle of our body. In the walls of our hollow organs like stomach, intestine, uterus, blood and blood capillaries, etc. smooth muscles are present. Involuntary muscles possess a single nucleus that is located in the center, and these muscles are spindle in shape. For these muscles, motor neurons of the autonomic nervous system are worked as a neurotransmitter.

There is a gap junction between the cells of involuntary muscles, and signals of neurons are transmitted from one to another cell. Involuntary muscle also plays an important role during stress conditions in which they give a response to stress by releasing the fluid in the stressed organ. Involuntary muscles are also said as unstriated muscles or unstriped muscles. As we know that these muscles are also present in the walls of internal organs, so they are also called “visceral muscles.” The reason why they are known as involuntary muscles is that because they are not under the desire of an individual.

The shape of involuntary muscles is spindle-like, thin, long muscle fiber. They are structurally very simple and keep an oval-shaped nucleus in each cell of the muscle. The oval-shaped nucleus is covered by the sarcoplasm called myofibrils. On involuntary muscles, there are no light or dark bands present. Instead of the dark or light band, there is actin or myosin is present. The involuntary muscles are firmly joined with the help of intercalated discs. These intercalated discs help the muscle in synchrony.

Key Differences

  1. Voluntary muscles present in the form of bulk in the body flash; on the other hand, involuntary muscles are present only in hollow organs.
  2. Voluntary muscles show a slow response; on the other side, involuntary muscles show a rapid response.
  3. Voluntary muscles involve conscious thoughts; conversely, involuntary muscles don’t involve conscious thought.
  4. Voluntary muscles are long; on the flip side, involuntary muscles are small.
  5. Voluntary muscles are under the will control; on the contrary, involuntary muscles not under the will control.
  6. Voluntary muscles experience a response to the benefit, although involuntary muscles experience a quick response to avoid danger.
  7. Voluntary muscles attached to the bones or tendons as compared to involuntary, which are not attached to the bones.
  8. Voluntary muscles possess many nuclei comparatively to the involuntary muscles that possess only single nuclei.
  9. Voluntary muscles get tired early; on the other hand, involuntary muscles don’t get tired early.
  10. Voluntary muscles are also known as the skeletal muscles; on the other side, involuntary muscles are also known as smooth muscles.

Conclusion

It is concluded that voluntary muscles are in our conscious, and involuntary muscles are not in our conscious.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White