Muscle Contraction

Front

What is the neuromuscular junction?

Back

The region where a motor neuron comes in close contact with a muscle cell, facilitating communication between the nervous system and muscle fibers.

Front

What does the all-or-none response mean in muscle contraction?

Back

It means that when a muscle fiber contracts, it contracts completely; there is no partial contraction.

Front

What causes an action potential in muscle cells?

Back

The imbalance of sodium (Na+) and potassium (K+) ions across the cell membrane.

Front

What two chemicals are necessary for muscle contraction to occur?

Back

Calcium and ATP (adenosine triphosphate) are essential for muscle contraction.

Front

What is the function of the sarcoplasmic reticulum?

Back

It stores calcium ions in the muscle cell, which are released during muscle contraction.

Front

Define muscle tension.

Back

The force generated by muscle fibers when they contract.

Front

What role does ATP play in muscle contraction?

Back

ATP provides the energy required for muscle contraction and relaxation.

Front

What is the role of calcium ions in muscle contraction?

Back

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

Front

What are actin and myosin?

Back

Actin and myosin are the two main proteins involved in muscle contraction; they form cross-bridges to generate force.

Front

What is the sliding filament theory?

Back

The theory that explains muscle contraction as the sliding of actin filaments over myosin filaments, shortening the muscle.