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Neuromuscular junction Fig. 11-12 Somatic motor neuron Muscle fiber The neuromuscular junction Motor end plate Terminal bouton Mitochondria Synaptic vesicle (ACh) Presynaptic membrane Synaptic cleft Postsynaptic membrane Schwann cell sheath Axon terminal Nicotinic ACh receptors
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Neuromuscular junction Fig. 11-13 Skeletal muscle fiber AChE Voltage-gated Ca 2+ channel Action potential ACh Ca 2+ Acetyl + choline Nicotinic receptor Motor end plate Somatic motor neuron Axon terminal K+K+ Na + K+K+ ACh Closed channel Open channel
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T-tubules and SR Fig. 12-4 Sarcolemma Thin filament Thick filament T-tubule brings action potentials into interior of muscle fiber. Sarcoplasmic reticulum stores Ca 2+
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Excitation-contraction coupling Axon terminal of somatic motor neuron Myosin head Myosin thick filament M line Motor end plate Sarcoplasmic reticulum ACh DHP RyR T-tubule Muscle fiber Troponin Tropomyosin Actin Z disk Na + Ca 2+ Ca 2+ released Myosin thick filament Fig. 12-11
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Troponin and tropomyosin Fig. 12-3 Thin filaments Tropomyosin Troponin Actin chain G-actin molecule Nebulin
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Cross-bridge cycle Fig. 12-9 ADP Actin moves Cytosolic Ca 2+ Tropomyosin shifts, exposing binding site on actin TN Power stroke Initiation of contraction Troponin G-Actin Tropomyosin blocks binding site on actin Myosin head TN Relaxed state. Myosin head cocked. Pi 1 2 3 4 5
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Types of Muscle Fibers Fig. 12-15
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SPINAL CORD Neuron 1 Neuron 2 Neuron 3 Motor nerve Muscle fibers Motor unit 2 Motor unit 1 Motor unit 3 One muscle may have many motor units of different fiber types. KEY Motor Units Fig. 12-15
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Basic circulatory system Fig. 9-2c, p.360
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Peristaltic heart
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One-way valves
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Chambered Heart
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Extrinsic Muscle Pump Extrinsic muscle Blood Valve
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Blood vessel structure Fig. 15-2
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Schematic view of mammalian circulation
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Mammalian circulation Fig. 14-1
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External anatomy of the heart Superior vena cava Right atrium Auricle of left atrium Aorta Pulmonary artery Right ventricle Left ventricle Coronary artery and vein Fig. 14-7
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Internal anatomy of the heart Right atriumLeft atrium Pulmonary semilunar valve Right pulmonary arteries Right ventricle Superior vena cava Left pulmonary arteries Aorta Left pulmonary veins Cusp of the AV (bicuspid) valve Cusp of a right AV (tricuspid) valve Chordae tendineae Inferior vena cava Papillary muscles Left ventricle Descending aorta Fig. 14-7
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Cardiac muscle structure Intercalated disks Myocardial muscle cell Fig. 14-7
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Intercalated discs
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