Q- Enlist four structural characteristics of a striated muscle fibre.
Answer- Striated muscle fibre:
Striated muscle fibre are found in the limbs, tongue, body wall, pharynx and all upper region of oesophagus.
The four structural characteristics of a striated muscle fibre are as follows:
1. The striated muscle fibres are arranged in a bundle manner that is called as fascicule.
2. Each striated muscle fibres are covered with a special covering called sacolemma, while the cytoplasm of striated muscle fibres has more mitochondria.
3. The striated muscle fibres are consisted of two types of bands: Light band and dark band. In it each dark band (that us also called A-band) has central light zone called Hensen’s line or H-zone, while the light band (that is also called I-zone) has dark zone of its centre called Z-line. The part of myofibril between two adjoining Z-lines is known as Sacolemma.
4. The striated muscle fibres are under control of human will that is why they are also called as voluntary muscle fibres.
Easy way to draw labelled diagram of Striated muscle fibre: