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Section X: Special Topics (B)

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A patient anesthetized using a halothane compound exhibits a marked rise in body temperature, a behavior indicative of malignant hyperthermia (HT). Select the one of the following statements that is NOT CORRECT:

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A. MH can arise from mutations that alter the amino acid sequence of the Na+-K+-ATPase.

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B. MH can arise from mutations that alter the amino acid sequence of the ryanodine-sensitive Ca2+ release channel.

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C. The muscle rigidity that occurs during MH is triggered by the presence of high concentrations of Ca2+ in the cytoplasm.

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D. MH can arise from mutations that alter the amino acid sequence of the voltage-gated, slow K type Ca2+ channel.

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E. MH can be treated by intravenous administration of dantrolene, which inhibits release of Ca2+ from the sarcoplasmic reticulum into the cytosol.

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Select the one of the following statements that is NOT CORRECT:

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A. F-actin is formed by the polymerization of G-actin.

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B. Myosin is the major component of the thick filaments found in striated muscle.

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C. Thin filaments are connected together by α-actinin.

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D. The troponin system regulates the contraction of smooth muscle.

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E. Ca2+ serves as a second messenger for regulating contraction in smooth, cardiac, and skeletal muscle.

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Select the one of the following that is NOT a feature of the contractile cycle in striated muscle:

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A. Binding of Ca2+ to troponin C uncovers the myosin binding sites on actin.

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B. The power stroke is initiated by the release of Pi from the actin-myosin-ADP-Pi complex.

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C. Release of ADP from the actin-myosin-ADP complex is accompanied by a large change in the conformation of myosin’s head domain (relative to its tail domain).

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D. The binding of ATP by myosin increases its affinity for actin.

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E. Rigor mortis results for the inability of actin to release from the actin myosin complex when cells are deficient in ATP.

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Select the one of the following that does NOT serve as a major energy reserve for replenishing ATP in muscle tissue:

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A. Glycogen

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B. Creatine phosphate

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