Muscle Physiology Review

Front

What are striations in muscles?

Back

Striations are alternating light (I) and dark (A) bands found in skeletal and cardiac muscle fibers, indicating the organized arrangement of actin and myosin filaments.

Front

What is fascia?

Back

Fascia is connective tissue that surrounds muscles and muscle cells, providing support and structure.

Front

Which type of muscle is NOT striated?

Back

Smooth muscle is not striated; it has a uniform appearance and is found in the walls of hollow organs.

Front

What happens when calcium binds to troponin?

Back

When calcium binds to troponin, it causes tropomyosin to change shape, exposing the active sites on actin for myosin binding.

Front

What constitutes a thin filament in muscle fibers?

Back

A thin filament is composed of actin, tropomyosin, and troponin.

Front

What is the role of myosin in muscle contraction?

Back

Myosin is a thick filament that interacts with actin to produce muscle contraction through cross-bridge cycling.

Front

Define the sliding filament theory.

Back

The sliding filament theory explains how muscles contract by the sliding of actin filaments over myosin filaments, shortening the muscle fiber.

Front

What is the function of tropomyosin in muscle contraction?

Back

Tropomyosin blocks the active sites on actin, preventing myosin from binding until calcium binds to troponin.

Front

What is the difference between skeletal and cardiac muscle?

Back

Skeletal muscle is striated, voluntary, and multinucleated, while cardiac muscle is striated, involuntary, and has intercalated discs.

Front

What is the role of troponin in muscle contraction?

Back

Troponin binds calcium and regulates the position of tropomyosin, allowing muscle contraction to occur.