Question 6: Fill-in-the-blank(s) Question. Correctly complete each of the statements given below by
selecting the most appropriate answer option for each blank from the set of options listed in the
parentheses immediately following each blank
(Botulinum toxin; Curare; Nerve gas organophosphate; Tetanus toxin) paralyzes skeletal
muscle in its contracted state by inactivating acetylcholinesterase.
(Calmodulin; Tropomyosin; Titin; Troponin) is the calcium-binding regulatory protein used
in skeletal muscle.
(much shorter; similar; much longer) in
Because a skeletal muscle fiber's action potential is
duration compared to its mechanical contraction/relaxation cycle, the effects of multiple, rapidly
applied stimulations can summate, leading to unfused or fused tetany.
(longer; similar; shorter) latent period, a
(faster; similar;
Compared to a skeletal muscle fiber contracting under a light load, one contracting under a heavy load
would exhibit a
slower) shortening velocity), and reach a
(lower; similar; higher) maximal shortening
distance.
(ligand-gated ryanodine channels in the
DHP proteins in skeletal muscle function as
sarcoplasmic reticulum membrane; mechanically-gated ryanodine channels in the sarcoplasmic
reticulum membrane; L-type voltage-gated channels in the plasma membrane; voltage sensors in the T-
tubules)
The change in membrane potential that occurs at the motor end plate in skeletal muscle in response to
binding of the neurotransmitter released by an innervating somatic motor neuron is a/an
(action potential; excitatory post-synaptic potential or EPSP; inhibitory post-synaptic potential or IPSP).
The neurotransmitter released by the somatic motor neuron innervating a skeletal muscle fiber is
(always acetylcholine; always norepinephrine; usually acetylcholine but occasionally and
atypically norepinephrine; usually norepinephrine but occasionally and atypically acetylcholine).
Voltage-gated sodium channels needed for action potential generation in skeletal muscle fibers are
found in abundance
(everywhere in the sacrolemma; everywhere except in the motor end
plate of the sarcolemma; nowhere in the sarcolemma; only in the motor end plate region of the
sarcolemma) of the muscle fiber.
