MUSCLE+MOVEMENT-MOLECULAR+HO+MARIEB

What are the three types of muscle tissue?

Skeletal, Cardiac, and Smooth muscle.

What is the primary function of calcium ions (Ca2+) in muscle contraction?

Calcium binds to troponin, causing a conformational change that moves tropomyosin away from active sites on actin.

What occurs during the cross bridge cycle?

Myosin heads bind to actin, pull the thin filaments toward the center of the sarcomere, and detach when ATP binds.

What are the main connective tissue sheaths of skeletal muscle?

Epimysium, Perimysium, and Endomysium.

What triggers the release of calcium ions from the sarcoplasmic reticulum?

Action potential traveling down T tubules.

How does acetylcholine (ACh) affect muscle contraction?

ACh binds to receptors on the muscle fiber, leading to depolarization and triggering an action potential.

What is the role of troponin and tropomyosin in muscle contraction?

Troponin binds calcium, which causes tropomyosin to move and expose myosin-binding sites on actin.

What is the difference between skeletal and cardiac muscle?

Skeletal muscle is long, cylindrical, and multinucleate; cardiac muscle is branched, uni- or binucleate, and has striations.

In the sliding filament model, what happens during muscle contraction?

Thin filaments slide past thick filaments, causing the sarcomere to shorten.

What energy sources do muscle fibers use for contraction?

ATP and creatine phosphate (CP) are primary energy sources.