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What are the roles of thick and thin filaments in muscle contraction?
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∙ 9y ago
The thin filaments are actin, and the thick filaments are myosin. The filaments run parrel to one another along the length of the sarcomere.
The dark bands that occur in the middle of the sarcomere are regions where the thick filaments and thin filaments overlap.
Wiki User
∙ 9y ago
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The sliding filament mechanism of muscle contraction involves?
during contraction, the thin filaments slide past the thick filaments so that actin and myosin filaments overlap.
1 Describe the ionic events underlying the nerve action potential 2. Describe the steps in cross bridge cycle that produces skeletal muscle contraction.?
thick filaments pulling thin filaments toward the center of the sarcomere
What is composed of myosin?
Thick Filaments
How can smooth muscle contract if it has no striation or sarcomeres?
Actin and myosin are present in all three muscle types. In skeletal and cardiac muscle cells, these proteins are organized in sarcomeres, with thin and thick filaments. The internal organization of a smooth muscle cell is very different: • A smooth muscle fibre has no T tubules, and the sarcoplasmic reticulum (SR) forms a loose network throughout the sarcoplasm. Smooth muscle tissue has no myofibrils or sarcomeres. As a result, this tissue also has no striations and is called nonstriated muscle. • Thick filaments are scattered throughout the sarcoplasm of a smooth muscle cell. The myosin proteins are organized differently than in skeletal or cardiac muscle cells, and smooth muscle cells have more cross-bridges per thick filament. • The thin filaments in a smooth muscle cell are attached to dense bodies, structures distributed throughout the sarcoplasm in a network of intermediate filaments composed of the protein desmin. Some of the dense bodies are firmly attached to the sarcolemma. The dense bodies and intermediate filaments anchor the thin filaments such that, when sliding occurs between thin and thick filaments, the cell shortens. Dense bodies are not arranged in straight lines, so when a contraction occurs, the muscle cell twists like a corkscrew. • Adjacent smooth muscle cells are bound together at dense bodies, transmitting the contractile forces from cell to cell throughout the tissue. • Although smooth muscle cells are surrounded by connective tissue, the collagen fibres never unite to form tendons or aponeuroses as they do in skeletal muscles.
A sarcomere is?
A sarcomere consists of thin and thick filaments arranged so they can slide over each other. The boundary of the sarcomere are the Z lines. Thin filaments extend from the Z lines and overlap with thick filaments in the middle of the sarcomere. The I band is on each side of the Z line where only thin filaments occur. The A band is the length of the thick filaments and is divided into three parts; the zone of overlap is on each end where thin and thick filaments occur, the H band is in the middle and has only thick filaments, and the M line is the center of the A band.
What happens when thin filaments in a muscles fiber slide over the thick filament?
Contraction or relaxation of muscle fibre, due to similar effect in sarcomere
What is the mechanical force of muscle contraction is generated by?
The mechanical force of muscle contraction is generated by a sliding of thin filaments past thick ones.
Which myofilaments actually do the pulling during the sliding filament model of muscle contraction?
thick filaments
Which Muscle movement in myosin heads of the thick filaments pull on the thin filaments causing the thin filaments to slide toward the center of the sarcomere?
Flexing of the cross bridge (power stroke)
Which of the following become connected by myosin cross-bridges during muscle contraction A) thin filaments and thick filaments B) thin filaments and t-tubules C) thick filaments and titin filame?
Interactions between actin and myosin filaments of the sarcomere are responsible for muscle contractions. The I bands contain only thin (actin) filaments, whereas the A bands contain thick (myosin) filaments.
Are there more thick filaments than thin filaments in smooth muscle?
There more thin filaments than thick filaments in smooth muscle. The ratio is of the thin to thick filaments in the smooth muscle is approximately 15:1.
Contraction in a muscle occurs because the?
thin filaments slide between the thick filaments Answer #2: Because the action potential reaches the end of the nerve, causing contraction. myofilaments increase the amount that they overlap
The sliding filament mechanism of muscle contraction involves?
during contraction, the thin filaments slide past the thick filaments so that actin and myosin filaments overlap.
What protein filament is usually always ready for muscle contraction?
The structure of muscle filaments - View diagram of the structure of muscle ... These two types of filament have different structures that enable then to work together. ... Thick filaments are formed from a protein called myosin which has important ...muscle filaments cause muscles to contract,
What are the thin fibers responsible for muscle contraction?
The thin myofilaments are actin. They slide between the thick filaments called myosin.
How does a muscle contact according to the sliding-filament model of muscle contraction?
When skeletal (or cardiac) muscle contracts, the thin and thick filaments in each sarcomereslide along each other without their shortening, thickening, or folding.
What muscle shapes the muscle?
thick and thin bands (lines) of filaments.
