Mechanism of Muscle Contraction

What is the structure that covers the myosin binding site on actin?

• tropomyosin

• troponin complex

• myosin head

• myosin tail

Which filament slides inward during muscle contraction

• Actin

• Myosin

What is the role of the Tropomyosin in muscle contraction?

• It blocks the myosin binding sites on actin.

• It provides the energy for muscle contraction.

• It is the site where acetylcholine is released.

• It is responsible for the release of calcium ions.

During full muscle contraction, which region disappear?

• I band

• M line

• H zone

• A band

What is sarcomere?

• A protein filament or fiber

• The functional unit of muscle fiber in the skeletal muscle

• An organelle

• An organ

The part of the sarcomere that labelled A (green) refers to?

• Z Line

• M Line

• H Line

• A Line

The location where the motor neuron reaches the sarcolemma of the muscle fiber is the _____.

• Neurotransmitter

• Acetylcholine

• Synaptic cleft

• Neuromuscular Junction

One neuron and all the skeletal muscle cells it stimulates is the ____ ___.

• Neurotransmitter

• Neuromuscular junction

• Motor unit

• Synaptic cleft

What is the specific neurotransmitter that stimulates the muscle contraction?

• GABA

• Acetylcholine

• Serotonin

• Dopamine

The neurotransmitter stored in the axon terminal identified as #3

• Acetylcholine

• Protein Channel

• Calcium Ion (Ca²⁺)

• Syanptic Cleft