Muscle Contraction and the Sliding Filament Model

What initiates the process of muscle contraction?

• A signal from the brain

• A signal from the lungs

• A signal from the heart

• A signal from the spinal cord

What is the neuromuscular junction?

• The connection between a neuron and a muscle cell

• The connection between two neurons

• The connection between a neuron and a bone

• The connection between two muscle cells

What role does the sarcoplasmic reticulum play in muscle contraction?

• It stores potassium ions

• It stores sodium ions

• It stores calcium ions

• It stores chloride ions

What happens when sodium rushes into the postsynaptic cell?

• The cell hyperpolarizes

• The cell depolarizes

• The cell remains unchanged

• The cell becomes inactive

What is the role of calcium in the sliding filament model?

• It blocks the binding sites

• It binds with troponin to expose binding sites

• It inhibits muscle contraction

• It provides energy for contraction

What is the function of ATP in muscle contraction?

• It inhibits the power stroke

• It binds with actin

• It breaks the cross bridge and resets the myosin head

• It blocks calcium release

What is the power stroke in muscle contraction?

• The release of calcium from the sarcoplasmic reticulum

• The release of ATP

• The binding of myosin to actin

• The pulling action of the myosin head on actin

What happens when calcium is pumped back into the sarcoplasmic reticulum?

• The muscle contracts

• The muscle relaxes

• The muscle remains contracted

• The muscle becomes hyperactive

What is the role of tropomyosin in muscle contraction?

• It binds with calcium

• It covers the binding sites on actin

• It provides energy for contraction

• It releases neurotransmitters

What is the final step in the sliding filament model?

• The depolarization of the muscle cell

• The relaxation of the muscle

• The formation of a cross bridge

• The release of calcium