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Published byBenjamin Rings Modified over 9 years ago
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The Organization of a Skeletal Muscle Figure 7-1
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Organization of a Skeletal Muscle Fiber Figure 7-2a
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Organization of a Skeletal Muscle Fiber Figure 7-2 b-c
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Sarcomere Shortening Figure 7-3
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Sarcomere Shortening Figure 7-3
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Structure and Function of the Neuromuscular Junction Figure 7-4 a
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Structure and Function of the Neuromuscular Junction Figure 7-4 b
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Structure and Function of the Neuromuscular Junction Figure 7-4
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Structure and Function of the Neuromuscular Junction Figure 7-4
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Structure and Function of the Neuromuscular Junction Figure 7-4
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Structure and Function of the Neuromuscular Junction Figure 7-4
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Structure and Function of the Neuromuscular Junction
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The Contraction Cycle Five Steps of the Contraction Cycle – Exposure of active sites – Formation of cross-bridges – Pivoting of myosin heads – Detachment of cross-bridges – Reactivation of myosin
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Molecular Events of the Contraction Process Figure 7-5 The active site is exposed following the binding of calcium ions to troponin.
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Molecular Events of the Contraction Process Figure 7-5 The myosin cross bridge forms and attaches to the exposed active site on the thin filaments.
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Molecular Events of the Contraction Process Figure 7-5 The attached myosin head pivots toward the center of the sarcomere and ADP and a phosphate group are released.
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Molecular Events of the Contraction Process Figure 7-5 The cross- bridges detach when the myosin head binds another ATP molecule
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Molecular Events of the Contraction Process Figure 7-5 The detached myosin head is reactivated as it splits the ATP and captures the released energy.
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Frequency of Muscle Fiber Stimulation Three Phases of Twitch – Latent period before contraction: The action potential moves through sarcolemma Causing Ca 2+ release – Contraction phase: Calcium ions bind Tension builds to peak – Relaxation phase: Ca 2+ levels fall Active sites are covered Tension falls to resting levels
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Twitch and Development of Tension Figure 7-6
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Effects of Repeated Stimulations Figure 7-7
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Types of Skeletal Muscle Fibers Fast fibers (White) – Light in color, large diameter – Few capillaries, few mitochondria – Uses glycolysis (2 ATP) – Little myoglobin – Power/speed – Fatigue rapidly
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Types of Skeletal Muscle Fibers Slow fibers (Red) Red in color, small diameter Many capillaries, numerous mitochondria Uses Krebs cycle/Oxidative phosphorylation (34 ATP) Much myoglobin High endurance
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Muscle Metabolism Figure 7-9
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Muscle Metabolism Figure 7-9
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Muscle Metabolism Figure 7-9
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