Order the events leading to muscle contraction. Ca ions bind to troponin myosin binds to actin Nerve cell releases acetylcholine at the neuromuscular junction troponin pulls tropomyosin, exposing the mysoin binding site ATP causing myosin to move (pull) actin toward the center of the cell the sarcolemma membrane depolarizes and triggers the sarcoplamic reticulum to release Ca ions

Seconds Put the steps of excitation-contraction in order: 1 Myosin "heads" pivot, cause [ Choose ] Calcium is taken back up and the muscle relaxes Action potential triggers Ca2+ release from sarcoplasmic reticulum ACh produces large EPSP in muscle fiber 4 Muscle contracts Binding of Ca2+ to troponin causes myosin to bind to actin 5. EPSP evokes muscle action potential Alpha motor neurons release ACh Myosin "heads" pivot, cause filaments to walk along filament 7 [ Choose ) 8. [Choose ]

Why does continuouns calcium release within a muscle fiber cause greater tension? Acticates more calcium pump  Activates myofibrils continuously  Increase action potential frequency  Lengthens sarcomere

Which of the following are part of the muscle contraction process?(More than one answer may be correct, please aid in answering) Question 5 options:   ATP binds and detaches myosin head from actin   GTP is hydrolyzed to GDP + P   Acetylcholine released into neuromuscular junction by motor neurons   Prolactin stimulates the reuptake of ATP.   Ca2+ binds to troponin which moves tropomyosin away from actin

Explain the requirements for Ca2+ and ATP in muscle contraction and relaxation.  Remember that myofibers are cells and have cellular metabolic requirements as well.

What step DIRECTLY causes a sarcomere to shorten? cross- bridge formation  calcium transport into SR calcium release  power stroke myosin heads in high energy state

Which of the following statements are true? (choose all that apply) The Z-disc is found in the middle of an l-band Myosin are known as the thick filaments The A-band is seen as "dark" under the microscope Tropomyosin is on the Actin filament During a muscle contraction, the sarcomeres move farther apart A sarcomere is located from one H-zone to the following H-zone

Describe and explain the sliding filament model of contraction. Be sure to include in your response a comparison between a relaxed and contracted sarcomere of a muscle fiber.

During the cross bridge cycle, what is the first event that occurs after ATP binds myosin? the power stroke occurs myosin releases actin myosin binds actin to form another cross bridge myosin enters its energized state

Distinguish between skeletal, smooth, and cardiac muscle in terms of location and whether they have sarcomeres. Use the sliding filament model to draw how thin filaments, thick filaments, and Z lines move during muscle contraction. Predict how perturbations of acetylcholine release, reception, or breakdown will influence muscle contraction. Predict how perturbations of actin, troponin, tropomyosin, myosin, or calcium would influence muscle contraction. Distinguish between the sympathetic and parasympathetic nervous system. Predict how changes in stress levels or situations would affect activation of the sympathetic and parasympathetic nervous system, levels of epinephrine and norepinephrine, and blood pressure.