Describe the structure of sarcomere.

1.	Describe the structure of sarcomere.
Answer» The portion of the myofibril between two successive ‘z’ lines is called as sarcomere. It is the functional unit of muscle contraction. A sarcomere consists of a dark band in the centre and light bands on either side. The dark band or Anisotropic band (A band) is made of myosin and the light band on Isotropic band (I- band) is made of actin filaments. Along the centre of the I- band is an elastic fibre called z – line, that bisects the band. Their filaments are attached firmly to the z – line. The myosin filaments are also held together in the centre by a thin fibrous membrane called M – Line. The central part of A band, not over lapped by thin filaments (I- band) is called a H – zone.

Answer»

The portion of the myofibril between two successive ‘z’ lines is called as sarcomere. It is the functional unit of muscle contraction. A sarcomere consists of a dark band in the centre and light bands on either side. The dark band or Anisotropic band (A band) is made of myosin and the light band on Isotropic band (I- band) is made of actin filaments.

Along the centre of the I- band is an elastic fibre called z – line, that bisects the band. Their filaments are attached firmly to the z – line. The myosin filaments are also held together in the centre by a thin fibrous membrane called M – Line. The central part of A band, not over lapped by thin filaments (I- band) is called a H – zone.

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