1. Copyright © 2009 Pearson Education, Inc. Figure 6.4b Muscle cells.

5. Copyright © 2009 Pearson Education, Inc. Figure 6.1a Movement of bones.

6. Copyright © 2009 Pearson Education, Inc. Figure 6.1b Movement of bones.

7. Copyright © 2009 Pearson Education, Inc. Figure 6.3 Muscle structure.

8. Copyright © 2010 Pearson Education, Inc. Figure 9.1a Connective tissue sheaths of skeletal muscle: epimysium, perimysium, and endomysium. Bone Endomysium (between individual muscle fibers) Muscle fiber Fascicle (wrapped by perimysium) Epimysium Tendon Blood vessel

9. Copyright © 2010 Pearson Education, Inc. NucleusLight I bandDark A band Sarcolemma Mitochondrion (b) Diagram of part of a muscle fiber showing the myofibrils. One myofibril is extended afrom the cut end of the fiber. Myofibril Figure 9.2b Microscopic anatomy of a skeletal muscle fiber.

10. Copyright © 2009 Pearson Education, Inc. Figure 6.5 Structure of a myofibril.

11. Copyright © 2010 Pearson Education, Inc. Figure 9.2e Microscopic anatomy of a skeletal muscle fiber. I band thin filaments only Actin filament Myosin filament H zone thick filaments only M line thick filaments linked by accessory proteins Outer edge of A band thick and thin filaments overlap (e) Cross-sectional view of a sarcomere cut through in different locations.

12. Copyright © 2009 Pearson Education, Inc. Figure 6.5d Structure of a myofibril.

13. Copyright © 2009 Pearson Education, Inc. Figure 6.8 Role of calcium in contraction.

14. Copyright © 2010 Pearson Education, Inc. Figure 9.12 Cross Bridge Cycle Actin Cross bridge formation. Cocking of myosin head. The power (working) stroke. Cross bridge detachment. Ca 2+ 1 2 3 4 Myosin head Thick filament Thin filament ADP Myosin P i ADP P i ATP hydrolysis ADP P i ATP

15. Copyright © 2010 Pearson Education, Inc. Figure 9.4 Transmission electron micrograph of part of a sarcomere clearly showing the myosin heads forming cross bridges that generate the contractile force. Thin filament (actin)Thick filament (myosin)Myosin heads

16. Copyright © 2009 Pearson Education, Inc. Figure 6.9a Motor units.

17. Copyright © 2010 Pearson Education, Inc. Figure 9.8 Events at the Neuromuscular Junction (1 of 4) Nucleus Action potential (AP) Myelinated axon of motor neuron Axon terminal of neuromuscular junction Sarcolemma of the muscle fiber

18. Copyright © 2009 Pearson Education, Inc. Figure 6.9b Motor units.

19. Copyright © 2010 Pearson Education, Inc. Acetylcholine, a neurotransmitter, diffuses across the synaptic cleft and binds to receptors in the sarcolemma. Figure 9.8 Events at the Neuromuscular Junction (2 of 4) Ca 2+ Axon terminal of motor neuron Synaptic vesicle containing ACh Synaptic cleft Fusing synaptic vesicles ACh Sarcoplasm of muscle fiber Ca 2+

20. Copyright © 2010 Pearson Education, Inc. Figure 9.8 Events at the Neuromuscular Junction (3 of 4) Postsynaptic mem- brane ion channel opens; ions pass. Na + K+K+ 5 ACh binding opens ion channels that allow simultaneous passage of Na + into the muscle fiber and K + out of the muscle fiber.

21. Resting Potential of muscle cells – –Potassium higher inside –Sodium higher outside –A voltage difference of about 90 mvolts Action Potential – –A wave of depolarization that propogates from the point of stimulation over the entire membrane, followed by a wave of repolarization.

22. Copyright © 2010 Pearson Education, Inc. Figure 9.9 Summary of events in the generation and propagation of an action potential in a skeletal muscle fiber. Na + K+K+ Axon terminal Synaptic cleft ACh– ACh 1 Local depolarization: Na + Open Na + Channel Closed K + Channel K+K+ K+K+ K+K+ 2 Generation and propagation of the action potential (AP) 3 Repolarization Sarcoplasm of muscle fiber Na +

23. Copyright © 2010 Pearson Education, Inc. Figure 9.5 Relationship of the sarcoplasmic reticulum and T tubules to myofibrils of skeletal muscle. Myofibrils Sarcolemma Mitochondria Terminal cisternae of SR T tubule Triad

24. Copyright © 2010 Pearson Education, Inc. Figure 9.11 Excitation-Contraction Coupling (3 of 4) Calcium ions are released. Steps in E-C Coupling: Terminal cisterna of SR Voltage-sensitive tubule protein T tubule Ca 2+ release channel Ca 2+ Sarcolemma Action potential is propagated along the sarcolemma and down the T tubules. 1 2