myosin. Both the proteins are arranged as rod-like structures, parallel to each other and also to the longitudinal axis of the myofbrils. Aetin filaments are thinner as compared to the myosin filaments, hence are commonly called thin and thick filaments respectively. In the centre of each 'I' band is an elastic fibre called 'Z line which bisects it. The thin filaments are firmly attached to the ' Z line. The thick filaments in the 'A' band are also held together in the middle of this band by a thin flbrous membrane called 'M' line. The 'A' and 'T bands are arranged alternately throughout the length of the myofibrils. The portion of the myofibril between two successive ' Z lines is considered as the functional unit of contraction and is called a sarcomere (Figure 20.2). In a resting state, the edges of thin fllaments on either side of the thick flaments partially overlap the free ends of the thick flaments leaving the central part of the thick filaments. This central part of thick filament, not overlapped by thin flaments is called the 'H' zone.

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Question Text	myosin. Both the proteins are arranged as rod-like structures, parallel to each other and also to the longitudinal axis of the myofbrils. Aetin filaments are thinner as compared to the myosin filaments, hence are commonly called thin and thick filaments respectively. In the centre of each 'I' band is an elastic fibre called 'Z line which bisects it. The thin filaments are firmly attached to the ' $Z$ line. The thick filaments in the 'A' band are also held together in the middle of this band by a thin flbrous membrane called 'M' line. The 'A' and 'T bands are arranged alternately throughout the length of the myofibrils. The portion of the myofibril between two successive ' $Z$ lines is considered as the functional unit of contraction and is called a sarcomere (Figure 20.2). In a resting state, the edges of thin fllaments on either side of the thick flaments partially overlap the free ends of the thick flaments leaving the central part of the thick filaments. This central part of thick filament, not overlapped by thin flaments is called the 'H' zone.
Updated On	Feb 16, 2023
Topic	Human Physiology
Subject	Biology
Class	Class 12
Answer Type	Video solution: 1
Upvotes	145
Avg. Video Duration	9 min

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