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What are the structures within the muscle fiber that shorten to cause skeletal muscle fiber contraction?
The structures within the muscle fiber that shorten to cause skeletal muscle contraction are called myofibrils. Myofibrils are composed of repeating units called sarcomeres, which contain thick and thin filaments made of proteins (actin and myosin). When the muscle fiber is stimulated by a nerve impulse, the myosin heads interact with the actin filaments to generate the force required for muscle contraction.
What are two myofilaments that slide past one another to allow muscle cells to contract?
The two myofilaments that slide past one another to enable muscle contraction are actin and myosin. Actin makes up thin filaments while myosin forms thick filaments. During muscle contraction, myosin heads attach to actin filaments and pull them towards the center of the sarcomere, causing the muscle to shorten.
What structure runs the length of the sarcomere through the thick filaments and contributes to the elastic recoil in muscle?
The structure that runs the length of the sarcomere through the thick filaments and contributes to the elastic recoil in muscle is the protein titin. Titin acts as a molecular spring, providing elasticity to the muscle and helping it return to its original length after contraction.
What do you call the stripes across a skeletal muscle cell?
The stripes across a skeletal muscle cell are called myofibrils, which are made up of repeating units called sarcomeres. Sarcomeres are responsible for muscle contraction and are composed of thick and thin filaments that give the muscle its striped appearance.
Does the width of the A band remain unchanged during contraction?
Yes, the width of the A band remains unchanged during muscle contraction. The A band corresponds to the length of the thick filaments (myosin), which do not change in length when the muscle contracts. Instead, during contraction, the I band and H zone decrease in width as the actin filaments slide over the myosin filaments. Thus, while the A band stays constant, the overall arrangement of the sarcomere changes.
What protein makes up the thick myofilament?
The protein that makes up the thick myofilament in muscle cells is called myosin. Myosin is a motor protein that plays a key role in muscle contraction by interacting with actin, the protein in the thin myofilament.
What is a compartment in a myofilament called?
A compartment in a myofilament is called a "sarcomere." Sarcomeres are the basic contractile units of muscle fibers, consisting of overlapping thick (myosin) and thin (actin) filaments. They are arranged end to end along the length of the myofibril, and their contraction leads to muscle shortening and force generation during movement.
What is myofilament?
Myofilaments are the protein fibers within muscle cells that slide past each other to cause muscle contractions. There are two main types of myofilaments: thin filaments, made up of actin protein, and thick filaments, made up of myosin protein. The interaction between these two types of filaments is essential for muscle contraction.
What is composed of myosin?
Myosin is a protein found in muscle cells that plays a key role in muscle contraction. It consists of long molecules called myosin filaments, which interact with actin filaments to generate the force needed for muscle movement.
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.
What chemicals are involved with contracting muscles?
Actin (thin myofilament), myosin (thick myofilament), calcium, and ATP (energy).
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
The thick filaments of muscle fibers are composed of what?
Myosin
Which myofilaments actually do the pulling during the sliding filament model of muscle contraction?
thick filaments
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 protein of the sarcomere is the thick filament made of?
The thick filament of the sarcomere is primarily made of the protein myosin. Myosin molecules aggregate to form the thick filaments, which interact with the thin filaments (primarily composed of actin) during muscle contraction. This interaction is crucial for the sliding filament model of muscle contraction, allowing muscle fibers to shorten and generate force.
In the sliding filament mechanism the thin filament is being pulled toward the?
M-line, causing overlap with the thick filament during muscle contraction. This results in the sarcomere shortening and overall muscle contraction.
