Site MapHelpFeedbackAction Potentials and Muscle Contraction (Quiz 2)
Action Potentials and Muscle Contraction (Quiz 2)

How do nerve impulses cause muscle contraction? Skeletal muscle is under voluntary control. Nerve impulses that originate in the central nervous system cause muscles to contract. Both neurons and muscle tissue conduct electrical current by moving ions across cellular membranes. A motor neuron ends in a synapse with a muscle fiber. The neuron releases acetylcholine and transfers the action potential to the muscle tissue. The signal will travel through the tissue and trigger the contraction of individual sarcomeres. One synapse generally controls an entire muscle fiber. One motor neuron usually controls several adjacent muscle fibers. A group of fibers under the control of a single motor neuron is known as a motor unit.

View the animation below, then complete the quiz to test your knowledge of the concept.






1An action potential causes calcium ions to diffuse from the ________ into the ________.
A)sarcoplasmic reticulum ; sarcolemma
B)sarcoplasmic reticulum ; sarcoplasm
C)sarcoplasm ; sarcoplasmic reticulum
D)sarcoplasm ; sarcolemma
E)sarcolemma ; sarcoplasm



2Which of the following best describes the role of Ca2+ in muscle contraction?
A)It binds to tropomyosin, moving troponin, so that myosin heads can bind to actin.
B)It binds to tropomyosin, moving troponin, so that actin heads can bind to myosin.
C)It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.
D)It binds to troponin, moving tropomyosin, so that actin heads can bind to myosin.
E)It binds to actin, moving myosin, so that troponin can bind to tropomyosin.



3All of the following are filamentous proteins EXCEPT
A)actin.
B)myosin.
C)troponin.
D)tropomyosin.
E)troponin and tropomyosin.



4An action potential causes depolarization of the T tubule membrane.
A)True
B)False



5T-tubules are invaginations of the sarcolemma of a muscle cell.
A)True
B)False







Animation Quiz SiteOnline Learning Center

Home > Biology 1 > Chapter 49 > Action Potentials and Muscle Contraction (Quiz 2)