Basis of differentiation | Voluntary muscles | Involuntary muscles |
Definition | Refer to muscles that are controlled by an individual’s will and are almost always associated with the skeleton system | Refer to muscles that are not controlled by an individual’s will and are often associated with organs that exhibit regular contractions and relaxation |
Also known as | Striated muscles or skeletal muscles | Non-striated muscles or smooth muscles |
Found in | Found attached to bones of the body by means of tendons. | Found lining the walls of internal organs in the body |
Shape of muscle cells | Muscle cells are long, cylindrical and unbranched | Muscle cells are small and spindle-shaped |
Composition of cell | Multinucleated with a large number of mitochondria | Uni-nucleated with one centrally located nucleus and fewer mitochondria |
Type of Sarcolemma surrounding the muscle fibers | Relatively thicker | Relatively thinner |
Sarcomeres | Present in muscle fibers | Absent |
Intercalated discs | Absent | Present in some types of involuntary muscles such as cardiac muscle |
Function | Involved in the movement and locomotion of body parts | Involved in internal movements of organs, facilitating the passage of fluids and food in the digestive system |
Contraction | Exhibit rapid and robust contractions | Exhibit slow, rhythmic contractions |
Energy requirement for contraction and relaxation | Have a high energy requirement | Have a low energy requirement |
Regulation | Regulated by the somatic nervous system | Regulated by the autonomic nervous system |
Nerve stimuli | Is generated from the outside by the nervous system | Is myogenic or generated within the muscle |
Fatigue and rest | Get fatigued easily and require regular intervals of rest | Do not fatigue and are able to work continuously |
Examples |
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