Muscle Contraction and the Sliding Filament Model

What is the primary focus of the sliding filament model?

• Explaining how muscles relax

• Describing the structure of bones

• Explaining how muscles contract

• Describing the function of nerves

In a relaxed muscle state, what covers the myosin binding sites on actin filaments?

• ATP molecules

• Myosin heads

• Tropomyosin

• Calcium ions

What initiates the process of muscle contraction?

• Release of calcium ions

• Action potential from a motor neuron

• Binding of ATP to myosin

• Relaxation of the sarcomere

What is the role of acetylcholine in muscle contraction?

• It binds to actin filaments

• It depolarizes the muscle fiber membrane

• It releases calcium ions

• It covers the myosin binding sites

What happens when acetylcholine binds to its receptor on the muscle fiber?

• Calcium ions are released

• The muscle fiber depolarizes

• ATP is synthesized

• The muscle fiber relaxes

What is the role of the neuromuscular junction in muscle contraction?

• It releases calcium ions

• It connects the motor neuron to the muscle fiber

• It stores ATP

• It covers the myosin binding sites

What is the function of T-tubules in muscle contraction?

• They transmit action potentials into the muscle fiber

• They cover myosin binding sites

• They store calcium ions

• They bind to acetylcholine

Where does the action potential travel after reaching the T-tubules?

• To the sarcoplasmic reticulum

• To the neuromuscular junction

• To the motor neuron

• To the actin filament

What is released from the sarcoplasmic reticulum to trigger muscle contraction?

• Sodium ions

• Potassium ions

• Chloride ions

• Calcium ions

What is the significance of the sarcomere in muscle contraction?

• It covers the actin filament

• It stores neurotransmitters

• It releases acetylcholine

• It is the basic unit of muscle contraction