Muscle Anatomy

Front

What is the myofibril?

Back

Myofibrils are long, thread-like structures found in muscle fibers that contain the contractile proteins actin and myosin, essential for muscle contraction.

Front

What is the function of the sarcolemma?

Back

The sarcolemma is the cell membrane of a muscle fiber that surrounds the myofibrils and is responsible for conducting electrical impulses.

Front

What is the role of mitochondria in muscle cells?

Back

Mitochondria are the powerhouses of the cell, providing energy (ATP) through aerobic respiration, crucial for sustained muscle activity.

Front

What is sarcoplasm?

Back

Sarcoplasm is the cytoplasm of a muscle cell, containing myofibrils, organelles, and various substances necessary for muscle function.

Front

What are Z lines?

Back

Z lines are the boundaries of a sarcomere, the basic unit of muscle contraction, where actin filaments are anchored.

Front

What happens to the Z lines during muscle contraction?

Back

During muscle contraction, the Z lines move closer together as the sarcomere shortens.

Front

What is the difference between actin and myosin?

Back

Actin is a thin filament that interacts with myosin, a thick filament, to facilitate muscle contraction.

Front

What is the epimysium?

Back

The epimysium is a connective tissue sheath that surrounds the entire muscle, providing structure and support.

Front

What is the function of troponin in muscle contraction?

Back

Troponin is a protein that binds calcium ions and helps regulate muscle contraction by controlling the interaction between actin and myosin.

Front

What is tropomyosin?

Back

Tropomyosin is a protein that wraps around actin filaments and blocks the binding sites for myosin, preventing contraction until calcium is present.