1. The document discusses the structure and function of skeletal muscle tissue. It describes the microscopic anatomy of skeletal muscle fibers and their myofibrils, sarcomeres, and filaments. 2. The contraction process is summarized, from the generation of an action potential to the sliding filament model. Key steps include calcium release, troponin/tropomyosin interaction, cross-bridge cycling powered by ATP hydrolysis. 3. Different types of muscle contractions - isometric, isotonic - and motor unit activation patterns - twitch, tetanus - are defined. Stimulus intensity controls muscle force through graded motor unit recruitment.

12. Figure 9.2a InterActive Physiology ®: Anatomy Review: Skeletal Muscle Tissue, pages 4-6 PLAY

13. Table 9.1a

14. Myofibrils Figure 9.3b InterActive Physiology ®: Anatomy Review: Skeletal Muscle Tissue, pages 7-8 PLAY

15. Structure and Organization Table 9.1b

19. Sarcomeres Figure 9.3c InterActive Physiology ®: Anatomy Review: Skeletal Muscle Tissue, page 9 PLAY

22. Figure 9.3c,d

24. Ultrastructure of Myofilaments: Thick Filaments Figure 9.4a,b

26. Ultrastructure of Myofilaments: Thin Filaments Figure 9.4c

28. Arrangement of the Filaments in a Sarcomere Figure 9.4d

32. The functional unit of a muscle fiber is the __________.

37. Skeletal Muscle Contraction Figure 10–9 (Navigator)

38. Skeletal Muscle Innervation Figure 10–10a, b (Navigator)

39. Neuromuscular Junction Figure 9.7 (a-c)

44. Na+ K+

54. Figure 9.10 Synaptic cleft Synaptic vesicle Axon terminal ACh ACh ACh Neurotransmitter released diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma.

55. Figure 9.10 Net entry of Na + Initiates an action potential which is propagated along the sarcolemma and down the T tubules. T tubule Sarcolemma Synaptic cleft Synaptic vesicle Axon terminal ACh ACh ACh Neurotransmitter released diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma. 1

56. Figure 9.10 Net entry of Na + Initiates an action potential which is propagated along the sarcolemma and down the T tubules. T tubule Sarcolemma SR tubules (cut) Synaptic cleft Synaptic vesicle Axon terminal ACh ACh ACh Neurotransmitter released diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma. Action potential in T tubule activates voltage-sensitive receptors, which in turn trigger Ca 2+ release from terminal cisternae of SR into cytosol. SR Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ 1 2

57. Figure 9.10 Net entry of Na + Initiates an action potential which is propagated along the sarcolemma and down the T tubules. T tubule Sarcolemma SR tubules (cut) Synaptic cleft Synaptic vesicle Axon terminal ACh ACh ACh Neurotransmitter released diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma. Action potential in T tubule activates voltage-sensitive receptors, which in turn trigger Ca 2+ release from terminal cisternae of SR into cytosol. Calcium ions bind to troponin; troponin changes shape, removing the blocking action of tropomyosin; actin active sites exposed. SR Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ 1 2 3

58. Figure 9.10 Net entry of Na + Initiates an action potential which is propagated along the sarcolemma and down the T tubules. T tubule Sarcolemma SR tubules (cut) Synaptic cleft Synaptic vesicle Axon terminal ACh ACh ACh Neurotransmitter released diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma. Action potential in T tubule activates voltage-sensitive receptors, which in turn trigger Ca 2+ release from terminal cisternae of SR into cytosol. Calcium ions bind to troponin; troponin changes shape, removing the blocking action of tropomyosin; actin active sites exposed. Contraction; myosin heads alternately attach to actin and detach, pulling the actin filaments toward the center of the sarcomere; release of energy by ATP hydrolysis powers the cycling process. SR Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ 1 2 3 4

59. Figure 9.10 Net entry of Na + Initiates an action potential which is propagated along the sarcolemma and down the T tubules. T tubule Sarcolemma SR tubules (cut) Synaptic cleft Synaptic vesicle Axon terminal ACh ACh ACh Neurotransmitter released diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma. Action potential in T tubule activates voltage-sensitive receptors, which in turn trigger Ca 2+ release from terminal cisternae of SR into cytosol. Calcium ions bind to troponin; troponin changes shape, removing the blocking action of tropomyosin; actin active sites exposed. Contraction; myosin heads alternately attach to actin and detach, pulling the actin filaments toward the center of the sarcomere; release of energy by ATP hydrolysis powers the cycling process. Removal of Ca 2+ by active transport into the SR after the action potential ends. SR Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ 1 2 3 4 5

60. Figure 9.10 ADP P i Net entry of Na + Initiates an action potential which is propagated along the sarcolemma and down the T tubules. T tubule Sarcolemma SR tubules (cut) Synaptic cleft Synaptic vesicle Axon terminal ACh ACh ACh Neurotransmitter released diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma. Action potential in T tubule activates voltage-sensitive receptors, which in turn trigger Ca 2+ release from terminal cisternae of SR into cytosol. Calcium ions bind to troponin; troponin changes shape, removing the blocking action of tropomyosin; actin active sites exposed. Contraction; myosin heads alternately attach to actin and detach, pulling the actin filaments toward the center of the sarcomere; release of energy by ATP hydrolysis powers the cycling process. Removal of Ca 2+ by active transport into the SR after the action potential ends. SR Tropomyosin blockage restored, blocking myosin binding sites on actin; contraction ends and muscle fiber relaxes. Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ Ca 2+ 1 2 3 4 5 6

63. Action potential review

68. Figure 9.12 ATP ADP ADP ATP hydrolysis ADP ATP P i P i Myosin head (high-energy configuration) Myosin head attaches to the actin myofilament, forming a cross bridge. Thin filament As ATP is split into ADP and P i , the myosin head is energized (cocked into the high-energy conformation). Inorganic phosphate (P i ) generated in the previous contraction cycle is released, initiating the power (working) stroke. The myosin head pivots and bends as it pulls on the actin filament, sliding it toward the M line. Then ADP is released. Myosin head (low-energy configuration) As new ATP attaches to the myosin head, the link between myosin and actin weakens, and the cross bridge detaches. Thick filament 1 4 2 3

73. Isotonic Contractions Figure 9.19a

74. Isometric Contractions Figure 9.19b

80. Figure 9.14b

84. Stimulus Intensity and Muscle Tension Figure 9.16

87. Length Tension Relationship Figure 9.22 There is an optimal length

99. Energy for Contraction Figure 9.20

100. Energy Source Creatine Phosphate Anaerobic glycolyis Aerobic respiration Oxygen Use no no yes Products 1 ATP creatine 2 ATP lactic acid 36 ATP CO 2 , H 2 O Duration 15 Seconds 30-60 seconds Hours

103. Smooth Muscle Figure 9.24

112. Table 9.3.1

113. Table 9.3.2

114. Table 9.3.3

115. Table 9.3.4