A theory that explains how muscles contract. Each http://www.answers.com/topic/sarcomere (the functional unit of the muscle) contains overlapping thin (see http://www.answers.com/topic/actin) and thick (see http://www.answers.com/topic/myosin) filaments that can be interconnected by cross bridges. According to the theory, a shortening of sarcomere length is brought about by the two types of filaments sliding past each other by means of a ratchet-like mechanism of the cross bridges. Strong intermolecular forces occurring between the myosin head and cross bridge, cause the head to tilt. By means of this so-called power stroke, the thin filaments are pulled into the space between the thick filaments in each sarcomere. Contraction is triggered by a stimulatory http://www.answers.com/topic/nerve-impulse that causes an http://www.answers.com/topic/action-potential to spread across the sarcomere. The action potential causes calcium ions to be released around the filaments, enabling the cross bridges from myosin to attach onto the actin (in the absence of calcium, the attachment sites are blocked by http://www.answers.com/topic/tropomyosin. http://www.answers.com/topic/adenosine-triphosphate provides the energy used by the ratchet mechanism. See also http://www.answers.com/topic/rigor-complex.
In the sliding filament theory of muscle contraction, the thin filament (actin) slides over the thick filament (myosin). Myosin is responsible for pulling the actin filaments towards the center of the sarcomere during muscle contraction.
M-line, causing overlap with the thick filament during muscle contraction. This results in the sarcomere shortening and overall muscle contraction.
The sliding filament theory is the model that best describes muscle contraction. It explains how actin and myosin filaments slide past each other, resulting in muscle fiber shortening and contraction. This theory is widely accepted in the field of muscle physiology.
thick filaments
decreased width of the H band during contraction
it was a collaboration between Jean Hanson and Hugh Huxley
Dear freind! there is not any filamnet sliding in isometric contraction and so there is no work...
The myosin myofilament pulls on the actin myofilament during muscle contraction. This interaction, known as the sliding filament theory, results in the shortening of the sarcomere and muscle contraction.
The sliding filament mechanism of muscle contraction involves the interaction between actin and myosin proteins within muscle fibers. When muscles contract, myosin heads bind to actin filaments, causing them to slide past each other and generate force. This process is driven by the hydrolysis of ATP to provide the energy needed for muscle movement.
In the sliding filament model of muscle contraction, the protein troponin has a calcium binding site on the troponin C subunit. When calcium binds to troponin C, it triggers a conformational change in the troponin-tropomyosin complex, allowing myosin heads to interact with actin and initiate muscle contraction.
A drug that interferes with cross-bridge formation would prevent the myosin heads from binding to actin filaments, impairing the sliding filament mechanism essential for muscle contraction. This would result in a decrease in muscle force generation and overall muscle contraction efficiency.
Sliding filament mechanism