BIOC32H3 : Skeletal muscle part 2
Document Summary
When a muscle contracts isometrically, tension increases in the muscle but the overall length of the muscle does not change. This occurs because there are two components to the muscle; a contractile component consisting of the thick and thin filaments (myosin and actin, respectively) and a series elastic component consisting of tendons and other connective tissues. During an isometric contraction, the contractile component shortens while the series elastic component lengthens such that there is no overall change in the length of the muscle. During an isotonic contraction, tension initially increases (isometrically) until it is sufficient to lift the load. At that point the muscle contracts isotonically (it shortens at a constant tension). During this period, both the series elastic and contractile components shorten meaning that the entire muscle shortens. A single stimulus to a muscle will lead to a muscle twitch.