A sarcomere is the fundamental unit of striated muscles, such as skeletal and cardiac muscles, that is responsible for muscle contraction and performance. Sarcomeres are made up of many parallel thin actin filaments and thick myosin filaments, and are arranged in a stacked pattern throughout muscle tissue.
Here are some key facts about sarcomeres:
Structure
Sarcomeres are arranged between two Z-lines, and contain an M-band and an elastic filament system made of titin.
Function
Sarcomeres generate force and bear loads. The interaction between actin and myosin proteins is the basis of how sarcomeres shorten, which causes muscles to change length.
Size
In vertebrate skeletal muscle, a sarcomere's resting length is about 2.5 millimeters.
Number
A single muscle cell can contain thousands of sarcomeres.
Disease
Understanding the molecular structure of sarcomeres can help us understand their role in health and disease. For example, the M-band is a shock absorber in contracting muscles, and its dysfunction can contribute to muscle disease.
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