Physiology of a muscle contraction

Which muscle characteristic allows the muscle to return to resting length after contraction?

• Contractility

• Excitability

• Extensibility

• Tension

What is the name of the plasma membrane surrounding each muscle fiber?

• T Tubule

• Sarcolemma

• Sarcoplasm

• Nucleus

What is the contractile unit of the muscle?

• Z disk

• Sarcomere

• Muscle fiber

• Muscle cell

What protein makes up the thick filaments?

• Troponin

• Tropomyosin

• Myosin

• Actin

What part of the muscle fiber stores Ca ions and releases them when stimulated?

• T tubule

• Sarcolemma

• Nucleus

• Sarcoplasmic reticulum

What is the name of the location where the neuron and muscle fiber meet?

• Sarcoplasm

• Sacolemma

• Neuromuscular junction

• Axon terminal

What is the name of the neurotransmitter that is released from the neuron to the sarcolemma?

• Acetylcholine

• Acetone

• ATP

• Calcium

Which of these occurs first during a muscle contraction?

• The nerve signal reaches the neuromuscular junction

• Ach is released and opens Na ion channels

• The sarcomere shortens

• The myosin binds to the actin

Which of these occurs last during a muscle contraction?

• The nerve signal reaches the neuromuscular junction

• Ach is released and opens Na ion channels

• The sarcomere shortens

• The myosin binds to the actin

After calcium is released from the SR, it helps to change the shape of which myofilament?

• actin

• myosin