What is a contractile unit of a myofibril?
1 Answer
Dec 3, 2016
Sacromere is the basic unit of contraction within a bundle of muscle fibres.
Explanation:
Each sarcomeres is surrounded by Z lines which denote the boundary from one sarcomeres to the next. I bands contain thin filaments, H bands contain thick filaments and A bands contains a mix of thin and thick filaments.
These differences in thickness produce the characteristic straitions of skeletal muscles.
Within a sarcomeres , thin filaments extend from Z lines to the centre of the sarcomeres, with the thick filaments in the middle. The thick filaments overlap the thin filaments, but never go as far as the Z lines. The two kinds of filaments slide in respect to one another causing the Z filaments to be pulled towards one another, creating a muscle contraction.
