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| Striated Muscle |
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| It is also known as striped or voluntary or skeletal muscle. |
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| The striated muscle occurs in bundles called fascicles. Each fascicle has a large number of muscle fibres that are held together by connective tissue. The individual muscle fibre is elongated, cylindrical and unbranched. Each fibre is bound by a thick and distinct limiting membrane called sarcolemma in addition to the cell membrane. The sarcolemma encloses a large amount of specialised cytoplasm called sarcoplasm. The muscle fibres are multinucleated and the nuclei are found situated towards the sarcolemma. The myofibrils present in the sarcoplasm exhibit a characteristic arrangement, resulting in the formation of striations. The striations are formed by the alternating dark bands and light bands. Each dark band or A-band represents the region of the myofibril in which both thick and thin filaments are present. Each light band or I band represents the region of the myofibril in which only thin filaments are present. |
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| The striated muscle has a rich supply of blood. It receives motor or afferent nerves from the brain and spinal cord. The contractions may be slow or rapid but always arrhythmic and not sustained. The muscle easily experiences fatigue since the energy expenditure is very high. It is described as voluntary since its functioning is under the control of our will. |
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| fig 5.58 Striated Muscle |
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| The striated muscle is usually found associated and attached to bones and represents what is commonly known as flesh. E.g. Muscles of limbs. It is also found in the diaphragm, eyelids and tongue. |
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