Skeletal Muscle Structure and Contraction

Which of the following is the correct order?

• Fascicle, muscle fiber, myofibril, sarcomere, myofilament

• Sarcomere, muscle fiber, fascicle, myofibril, myofilament

• Muscle fiber, fascicle, sarcomere, myofibril, myofilament

• Fascicle, muscle fiber, myofilament, myofibril, sarcomere

The heads of the myosin filaments are called ___ when they link the thin and thin filaments together

• Connections

• Cross-connections

• Cross-bridges

• Power stroke

What is the function of Ca⁺⁺ during a skeletal muscle contraction?

• Connecting to nebulin

• Connecting to tropomyosin

• Connection to myosin

• Connecting to troponin

D on the image would be

• Myofibril

• Sarcomere

• Sarcolemma

• Sarcoplasmic reticulum

The protein that covers the binding site on actin when a muscle is relaxed is called

• Troponin

• Nebulin

• Tropomyosin

• Myosin

This structure stores calcium in the muscle cell

• Sarcolemma

• Sarcoplasmic reticulum

• Sarcomere

• Sarcocalcium storage

The A band contains which type of filaments

• Only thick

• Only thin

• Both thick and thin

Which of the following occurs When ATP binds to the myosin head?

• Myosin head detaches from actin

• Myosin head forms cross-bridge

• Myosin undergoes power stroke

• Myosin releases calcium

Which of the following decreases during muscle contraction?

• M line

• A band

• H zone

• Z line

Ca⁺⁺ will be released from the sarcoplasmic reticulum when

• the action potential reaches the neuromuscular junction

• ATP binds to sarcoplasmic reticulum

• Acetylcholine enters the synaptic cleft

• Action potential travels along T tubules