Skeletal Muscle Contraction and Excitation-Contraction Coupling

These flashcards cover key vocabulary related to skeletal muscle contraction, excitation-contraction coupling, and the biochemical processes involved in muscle action.

Power Stroke

The key force generating step utilized by myosin filaments to pull actin.

Excitation-Contraction Coupling

The process through which an action potential leads to muscle contraction.

Cytosolic Ca2+

Calcium ion concentration in the cytosol that triggers muscle contraction.

Troponin

A protein that, when bound to calcium, causes tropomyosin to move and expose binding sites on actin.

Tropomyosin

A protein that covers binding sites on actin filaments in their resting state.

Myosin

The thick filament protein responsible for muscle contraction through its interaction with actin.

Actin

The thin filament protein that interacts with myosin during muscle contraction.

Neuromuscular Junction

The site where a motor neuron transmits a signal to a muscle fiber.

Acetylcholine (ACh)

A neurotransmitter that transmits action potentials from nerve to muscle.

ATP Hydrolysis

The breakdown of ATP into ADP and inorganic phosphate, providing energy for muscle contraction.

Motor Unit

A single motor neuron and all the muscle fibers it innervates.

Calcium Release from SR

Calcium ions released from the sarcoplasmic reticulum that activate muscle contraction.

Actomyosin

The complex formed when myosin binds to actin.

Peripheral Fatigue

A decrease in the contractile strength of muscle fibers during intense exercise.

Sliding Filament Theory

The theory that muscle contraction occurs by the sliding of actin and myosin filaments past one another.

Sarcoplasmic Reticulum (SR)

An organelle that stores calcium ions and plays a key role in muscle contraction.