Muscle Structure & Function Review

Front

What is the role of troponin in muscle contraction?

Back

Troponin blocks myosin binding sites on actin, preventing contraction until calcium ions bind to it.

Front

What are the structural units that make up myofibrils?

Back

Myofibrils are made up of myofilaments, which include actin and myosin.

Front

What causes the striped appearance in skeletal muscles?

Back

The striped appearance is due to the arrangement of actin and myosin filaments.

Front

Which protein is primarily responsible for forming the thick filaments in muscle fibers?

Back

Myosin is the protein that forms the thick filaments in muscle fibers.

Front

What property do muscles lack if they cannot return to their original length after stretching?

Back

If muscles cannot return to their original length, they lack elasticity.

Front

Define muscle contraction.

Back

Muscle contraction is the process where muscle fibers shorten and generate force.

Front

What is the function of tropomyosin in muscle fibers?

Back

Tropomyosin blocks myosin binding sites on actin in a relaxed muscle.

Front

Explain the sliding filament theory.

Back

The sliding filament theory describes how actin and myosin filaments slide past each other to produce muscle contraction.

Front

What is the role of calcium ions in muscle contraction?

Back

Calcium ions bind to troponin, causing a conformational change that allows myosin to bind to actin.

Front

What is the difference between voluntary and involuntary muscles?

Back

Voluntary muscles are controlled consciously (e.g., skeletal muscles), while involuntary muscles operate automatically (e.g., cardiac and smooth muscles).