The sliding filament theory

Front

What is the sliding filament theory?

Back

The sliding filament theory explains how muscles contract by the sliding of actin (thin filaments) over myosin (thick filaments), resulting in muscle shortening.

Front

What is actin?

Back

Actin is a protein that forms the thin filaments within a muscle fiber.

Front

What role does calcium play in muscle contraction?

Back

Calcium binds to troponin on the actin filaments, allowing myosin heads to bind to actin and form cross-bridges.

Front

What is myosin?

Back

Myosin is a protein that forms the thick filaments within a muscle fiber and interacts with actin to facilitate muscle contraction.

Front

Define a crossbridge in muscle contraction.

Back

A crossbridge is the connection formed when myosin heads bind to actin filaments during muscle contraction.

Front

What is a muscle fiber?

Back

A muscle fiber is another name for a muscle cell, which is the basic unit of muscle tissue.

Front

What is the role of ATP in muscle contraction?

Back

ATP provides the energy required for myosin heads to detach from actin and re-cock for another contraction cycle.

Front

What happens during the power stroke in muscle contraction?

Back

During the power stroke, the myosin head pivots and pulls the actin filament toward the center of the sarcomere, causing muscle contraction.

Front

What is troponin?

Back

Troponin is a protein that, when bound to calcium, causes a conformational change that allows myosin to bind to actin.

Front

What is tropomyosin?

Back

Tropomyosin is a protein that covers myosin-binding sites on actin filaments, preventing contraction when calcium is not present.