Answer Happy

1. The principal role of calcium in skeletal muscle
contraction is to
a. participate in the propagation of an action potential along the
surface of the muscle fiber.
b. bind troponin, which in turn permits tropomyosin to uncover the
cross-bridge binding site on the thin filament.
c. bind tropomyosin, which in turn permits troponin to uncover the
cross-bridge binding site on the thin filament.
d. activate a calcium-calmodulin-dependent protein kinase, which in
turn phosphorylates and activates myosin.
2. In skeletal muscle depolarization of the T tubule
membrane causes
a. activation of Ca2+ ATPase pumps which
triggers a rise in intracellular calcium levels
b. dihydropyridine to bind calcium channel receptors which
triggers a rise in intracellular calcium levels.
c. activation of stretch-activated
Ca2+ channels which triggers a rise in
intracellular calcium levels.
d. activation of dihydroxypyridine receptors in membrane of
the T tubule which triggers a rise in intracellular calcium
levels.
e. ryanodine to bind calcium channel receptors which triggers
a rise in intracellular calcium levels.