Muscle Quiz



{H&E stains of tendon and skeletal muscle can appear remarkably similar. Which of the following are good ways to distinguish these cell types by light micrscopy(select as many as apply): + only skeletal muscle has striations about 1 micron wide + nuclei of tendon are flat, and very slender compared with ovoid skeletal muscle nuclei - skeletal muscles appear multinucleated by light miscroscopy - tendon darker due to compact collagen; skeletal muscle is lighter due to composition of actin/myosin + skeletal muscle is more likley to contain vascular and nervous structures + in cross section, skeletal muscle nuclei are located in the peripherial locations around nuclei; tendon nuclei are scattered randomly
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{Which type of muscle cell contraction requires calcium? - skeletal and smooth muscle only - skeletal and cardiac muscle only - smooth and cardiac muscle only + cardiac, smooth, and skeletal muscle - Ca++ is not required for contraction in any muscle
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{All of the following occur at the site of neuromuscular junction EXCEPT: - the nerve loses its myelin sheath - mitochondria accumulate in the presynaptic cell + the stimulated neuron releases vesicles containg Ca++ into the muscle - residual acetylcholine is hydrolyzed by cholinesterase bound to the basement membrane of the synaptic cleft
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{Which type of tissue is pictured above? - tendon (inflamed) + cardiac muscle - skeletal muscle - smooth muscle - brown fat - sensory ganglion (DRG)
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{What is the function of the perimysium? + Mechanically transmit forces generated by muscle contraction - Provide a physical barrier to inflammatory cells - Transmit the action potential from an efferent motor nerve - Provide substrate for myosin in muscle contraction
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{Which is true about the polarity skeletal muscle fibers? + Actin fibers exhibit opposite polarity on each side of the Z-line - Actin polarity is uniform in a sarcomere; myosin is non-polar (move bidirectionally) - Actin is a non-polar fiber - Directionality of muscle contraction is determined by actin polarity; myosin is non-polar
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