Excitation-Contraction Coupling and Cross-Bridge Cycle in Muscle Contraction

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What is the role of calcium in the Excitation-Contraction Coupling process?

Triggers the release of calcium from the T-tubules

Stimulates myosin to bind ATP

Inhibits the action potential propagation

Activates the ryanodine receptor to release stored calcium (correct)

What happens when myosin binds another ATP molecule?

It enters a state of rigor mortis

It detaches from actin (correct)

It activates the T-tubules

It binds stronger to actin

What occurs during the latent period of a twitch contraction?

Tension increases but not visibly

Peak tension is reached

Myosin binds to actin

AP propagation along T-tubules (correct)

How does an action potential contribute to muscle contraction?

Increases cytosolic calcium levels Signup and view all the answers

What is the significance of the Cross-Bridge Cycle in muscle contraction?

Facilitates the sliding of actin and myosin filaments Signup and view all the answers

When does muscle relaxation occur?

When cytosolic calcium levels decrease Signup and view all the answers

What is the main reason for using acetylcholinesterase inhibitors in treating certain conditions?

To inhibit the breakdown of acetylcholine, prolonging its action Signup and view all the answers

Why are glucocorticoids sometimes used in treatments related to neural causes?

To decrease inflammation in neural tissues Signup and view all the answers

In smooth muscle cells, what is responsible for anchoring thin filaments in place during contraction?

Dense bodies or dense plaques Signup and view all the answers

What is the characteristic feature of smooth muscles that distinguishes them from skeletal muscles regarding their striped appearance?

Presence of sarcomeres Signup and view all the answers

In smooth muscle contraction, which protein directly binds with calcium ions to initiate the process?

Calmodulin Signup and view all the answers

What type of electrical activity allows some smooth muscle cells to generate action potentials without external signals?

Slow waves Signup and view all the answers

What is the term for muscle contraction that produces tension and causes the muscle to change length?

Concentric contraction Signup and view all the answers

What happens to the muscle length in eccentric contraction?

The muscle lengthens Signup and view all the answers

What type of contraction occurs when the muscle changes tension but the length of the muscle stays the same?

Isometric contraction Signup and view all the answers

What is the effect of increasing load on shortening velocity of a muscle?

Shortening velocity decreases Signup and view all the answers

What does passive tension in a muscle refer to?

Tension due to titin protein Signup and view all the answers

What happens to the tension in a muscle if a second action potential is produced before the muscle relaxes from the first?

Tension increases Signup and view all the answers