Q:

What are involuntary muscles?

A:

According to Biology-Online, involuntary muscles are muscles which contract without conscious control, and typically found inside internal organs, excluding the heart. The heart, as noted by TeachPE.com, contains cardiac muscle. Cardiac muscle is excluded from the definition of involuntary muscle because it is highly specialized and resembles skeletal muscles, the voluntary muscles which attach to bone, more than it does the involuntary muscles found within other major organs.

TeachPE.com adds that involuntary muscle found in other organs is sometimes called "smooth muscle." Involuntary muscles are found in the stomach, esophagus and lungs, as well as in the walls of blood vessels. While both cardiac and skeletal muscle contain pronounced stripes, involuntary muscle does not. Uic.edu states that involuntary muscle contracts much more slowly than does skeletal muscle. University of Illinois at Chicago says smooth muscle is classified based on the make-up and alignment of the fibers within the muscle; in single-unit smooth muscle, fibers run parallel to each other and contain connections between one other, while in multi-unit smooth muscle, there are no connections.

Smooth muscle is controlled by the autonomic nervous system in contrast to skeletal muscles, which receive signals from the somatic nervous system. As Medline Plus explains, the autonomic nervous system is specialized to handle involuntary actions, including breathing, swallowing, blood pressure and heartbeat.


Is this answer helpful?

Similar Questions

  • Q:

    What is the difference between voluntary and involuntary movements?

    A:

    Some of the movements animals make are under conscious control, and are called voluntary movements. By contrast, other movements occur without the animal's conscious decision to do so. These types of movements are called involuntary movements or reflexes.

    Full Answer >
    Filed Under:
  • Q:

    Where are involuntary muscles found?

    A:

    Involuntary muscles are found in the circulatory system, digestive system and urinary system. Humans do not exert any control over these muscles, which is why they are called involuntary.

    Full Answer >
    Filed Under:
  • Q:

    What are examples of involuntary muscles?

    A:

    Examples of involuntary muscles, also known as smooth muscles, are the muscles of the urogenital tract, digestive tract, circulatory system and respiratory tract. Involuntary muscles are not controlled by the organism's will. Their actions are automatic and facilitated by the autonomic nervous system.

    Full Answer >
    Filed Under:
  • Q:

    Why are my muscles soft?

    A:

    The onset of soft muscles can be a symptom of many possible diseases, as explained on Right Diagnosis from Healthgrades. It can also be an indicator of a more immediate problem, such as muscle overuse, an electrolyte imbalance, a spinal injury or dehydration. Soft and weak muscles are sometimes combined with a wide variety of other symptoms including respiratory, nerve, pain, sensory, skin and movement problems.

    Full Answer >
    Filed Under:

Explore