From sarcomeres to whole muscles.
The series connection of sarcomeres in a muscle raises the possibility of instabilities due to some sarcomeres being capable of greater isometric tension than others, due to non-uniform activation, cross-sectional area or sarcomere length. Such instabilities are heavily damped by the force-velocity curve and stabilized by passive tension. The variation of active tension with sarcomere length may act to stabilize or destabilize the situation. Such instabilities can affect tension in a complex manner, causing both increases and decreases in different situations. Some examples of situations where sarcomere nonuniformities have been observed or inferred are given, and their mode of action explained.
D000818:Animals; D009119:Muscle Contraction; D009132:Muscles / Q000502:physiology*; D009210:Myofibrils / Q000502:physiology*; D012518:Sarcomeres / Q000502:physiology*