Our muscle structure consists of densely packed groups of elongated cells known as muscle fibres.
- Skeletal muscle is composed of bundles of long striated fibres.
- Smooth muscle which is found in the walls of internal organs such as intestines is made of short spindle-shaped fibres packed together in layers.
- Cardiac muscle found only in the heart has short interconnecting fibres.
- These fibres are held together by fibrous connective tissue.
- Capillaries penetrate this tissue to keep the muscles supplied with oxygen and nutrients that are needed to fuel contraction.
- In a relaxed muscle the thick and thin threads within a muscle fibre overlap a little.
- When a muscle contracts, the thick filaments slide further in between the thin filaments like interlacing fingers. This action shortens the entire fibre.
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