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During muscle contraction, the primary fibers used are myofibrils, which consist of two main types of protein filaments: actin (thin filaments) and myosin (thick filaments). When a muscle cell is stimulated, myosin heads attach to actin filaments and pull them inward, resulting in the shortening of the muscle fiber. This process is known as the sliding filament theory, and it is essential for muscle contractions in both skeletal and cardiac muscles.
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What are the units of contraction within a muscle fiber called?
The units of contraction within a muscle fiber are called sarcomeres. Sarcomeres are the basic functional and structural units of striated muscle tissue, composed of actin and myosin filaments. They are organized in a repeating pattern along the length of the muscle fiber, allowing for coordinated contraction and relaxation during muscle activity.
How do T-tubules contribute to the contraction of muscle fibers?
T-tubules are structures in muscle cells that help transmit electrical signals for muscle contraction. They allow for the rapid spread of these signals throughout the cell, ensuring coordinated muscle fiber contraction.
What best describes the events of excitation in excitation-contraction coupling?
cross bridge formation "Excitation-contraction coupling" connects muscle fiber excitation to the muscle fiber contraction (cross bridge formation). During contraction, myosin heads form cross bridges many times-with each cross bridge generating a small amount of tension in the muscle fiber.
What is the process of excitation contraction coupling?
cross bridge formation "Excitation-contraction coupling" connects muscle fiber excitation to the muscle fiber contraction (cross bridge formation). During contraction, myosin heads form cross bridges many times-with each cross bridge generating a small amount of tension in the muscle fiber.
What shortens contraction?
The interaction between actin and myosin filaments in muscle cells shortens the sarcomere during a contraction. Calcium ions released from the sarcoplasmic reticulum trigger this interaction, leading to the sliding of actin filaments over myosin filaments and shortening of the muscle fiber.
What do you call a shortening of muscle fiber?
contraction
What cellular organelle in muscle fiber corresponds to the endoplasmic reticulum?
The sarcoplasmic reticulum in muscle fiber corresponds to the endoplasmic reticulum in other cell types. The sarcoplasmic reticulum is a specialized type of endoplasmic reticulum found in muscle cells, and it plays a key role in calcium storage and release during muscle contraction.
What is shortening of a muscle fiber called?
a contraction human avatommy
What is a twitch contraction?
A twitch contraction is a single, brief contraction of a muscle fiber in response to a stimulus. It is the smallest unit of muscle contraction and is not strong enough to produce movement of a limb.
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 does contraction mean in medical terms?
contract or "contraction" is when a muscle fiber lengthens or shortens
What are all muscle cells called?
A single muscle cell is called a muscle fiber.
