Language
Country/Area
No result found
The Secret of Muscle Contraction: How Does the Sliding Ribbon Theory Overturn Traditional Concepts?
When exploring biological functions, the mechanism of muscle contraction is undoubtedly one of the most fascinating topics. Traditionally, people have had various different theories about how muscles contract, but the introduction of the sliding ribbon theory in the 1950s changed all that. This theory, which detailed how muscle proteins slide over each other to generate movement, amazed the biomedical community and became the foundation of muscle physiology.
The sliding ribbon theory states that the myosin (thick filaments) of a muscle fiber slide over the actin (thin filaments) during contraction, while the lengths of the two sets of fibers remain relatively constant.
History of the Sliding Ribbon Theory
Early Research Work
The roots of the sliding ribbon theory can be traced back to the late 19th and early 20th centuries. In 1864, German scientist Willy Kühne first discovered and named myosin, laying a foundation for subsequent muscle research. In 1939, a husband-and-wife Russian research team discovered that myosin has the properties of an enzyme that can break down ATP to release energy. Subsequently, Hungarian physiologist Albert Szent-Györgyi confirmed in 1942 that ATP is the energy source for muscle contraction.
The Sliding Ribbon Theory
In 1954, Andrew Huxley and Rolf Niedergerke of Cambridge University and Hugh Huxley and Jane Jean Hanson published two epoch-making papers, formally proposing the sliding ribbon theory. Although the experimental data of the two papers are different, their conclusions are similar, both pointing out that when muscles contract, actin slides into the A band of myosin.
Hacksley expressed it in 1953: "The extension of the muscle is not caused by the elongation of the filaments, but by the sliding of two sets of filaments."
Theory Acceptance and Influence
Despite the strong evidence, the sliding ribbon theory did not gain widespread support in its first few years. Doubts and rebuttals from many famous scientists caused this theory to fall into obscurity. With the advancement of technology in the 1960s, Huxley and other researchers finally captured evidence of the interaction between actin and myosin, making the sliding ribbon theory gradually gain widespread acceptance.
Cross-bridge mechanism
An important breakthrough in solving the Huxley problem was the proposal of the "cross-bridge model", which explains in detail how muscle fibers generate contraction force through the cyclic attachment and detachment of myosin and actin. This process is called the cross-bridge cycle and describes how muscles achieve precise movement and control during operation.
ConclusionAs myosins pull actin toward the center of the A-band, they break away and create a new force to bind the next actin molecule, Huxley concluded.
The sliding ribbon theory not only overturns the traditional understanding of muscle contraction, but also opens new doors for future biomedical research. With the development of science and technology, how will this theory further deepen our understanding of muscle physiology?
