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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.
What are individual muscle cells termed?
Another name is myocyte. It is formed from a myoblast. There are three types: smooth, striated and cardiac cells.
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.
Interactions between actin and myosin filaments of the sarcomere are responsible for what?
muscle relaxation
What are the roles of thick and thin filaments in muscle contraction?
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.
Which myofilaments actually do the pulling during the sliding filament model of muscle contraction?
thick filaments
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 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.
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.
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.
How does a muscle contract according to the sliding-filament model of muscles 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 is the name of the theory muscle contraction illustrated in the transparency?
In short, the basic contraction unit of the muscle is the sarcomere. Many sarcomeres work serially and in parallel to acheive the full contraction ability of the muscle. The sarcomere is made up of many filaments of Actin and Myosin, two types of protein based filaments that reach out towards each other from opposing sides of the sarcomere. When the muscle is at rest, the Actin and myosin filaments overlap each other the least. In order for the muscle to contract, the filaments from the opposing sides slide over each other thus pulling both walls of the sarcomere towards each other, with them. When the muscle is fully contacted, the filaments overlap each other the most. The sliding motion is activated by calcium that floods the sarcomeres (at the end of a process that is triggered by a command from a motor nerve). The calcium reveals sites on the Actin filaments at which molecular 'whips' extending from the Myosin filaments, can throw themselves, attach, pull, and leave, using the muscle's energy reserves in the process. Each molecular whip works at its own time (much like cylinders in an internal combustion engine), so that in any given time, contact between the filaments is being made by some of the whips.
What muscle cell filaments come closer together when the sarcomere shortens?
thin filaments
The filaments are arranged along the muscle fiber in units called?
Actin filaments
What muscle shapes the muscle?
thick and thin bands (lines) of filaments.
What are the names of protein filaments in a muscle fiber?
Actin Filaments
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,
