(Answered)Bio 264 Exam 3 2022
What structure runs from Z line to Z line? - Answer Sarcomere
The movement of the troponin-tropomyosin complex requires _______ - Answer
Ca2+.
The actin filament is a polymer formed from 300 to 400 globular subunits called
______ - Answer G-actin.
A myofilament is the _________. - Answer Protein strand composed of actin or
myosin
T tubules ________. - Answer Conduct action potentials deep into the muscle cell
Arrange these structures as they participate in excitation-contraction. - Answer
Sarcolemma, T tubules, sarcoplasmic reticulum, calcium ions
A drug that interferes with the active transport of calcium ions from the sarcoplasm
back into the sarcoplasmic reticulum would result in _______. - Answer Contraction
with no relaxation
The refractory period ______. - Answer Is the time during which the tissue cannot
respond again
Cardiac muscle cells are like skeletal muscle cells in that they both ________. -
Answer have striations
A child ingested an organophosphate poison used to kill insects. Soon the child's
muscles began tetanic contractions. Predict what occurred at the synaptic cleft. -
Answer Both increased accumulation of acetylcholine in the synapse and increased
breakdown of acetylcholine in the synaptic cleft.
Predict the consequences of administration of a compound that blocks the calcium
channels on presynaptic motor neuron terminals.
A. This should ultimately inhibit the release of acetylcholine
B. This should ultimately inhibit the muscle membrane from depolarization
C. This should ultimately inhibit the release of calcium from the sarcoplasmic
reticulum
D. All of the above are correct answers - Answer D. All of the above are correct
answers
Predict the consequences of administration of a compound that inhibits
acetylcholinesteras - Answer The muscle will stay contracted
Botulism food poisoning results from a toxin (poison) produced by bacteria. Death
from botulism results from the uncontrolled relaxation of the respiratory muscles
(diaphragm). Assuming that this toxin affects the neuromuscular junction, which of
the following could be a way in which this toxin could cause these muscles to relax
and no longer contract. - Answer The botulism toxin could block the release of
acetylcholine from the pre-synaptic terminal of a neruomuscular junciton.
, (Answered)Bio 264 Exam 3 2022
Myofibrils are composed primarily of ________. - Answer Actin and myosin
Neurotransmitters are stored in vesicles in _________. - Answer Motor neuron
endings
Which of the following statements is correct? - Answer Actin filaments slide along
myosin filaments.
Release of ACh - Answer Increases permeability of the sarcolemma.
Binding of ________ to myosin permits cross-bridge _____________ between actin
and myosin. - Answer ATP; detachment
Myosin myofilaments are - Answer attached to filaments that form the M line.
The part of the sarcolemma that invaginates into the interior of skeletal muscle fibers
is the - Answer T tubule system.
Somatic motor neurons release the neurotransmitter _________ at the
neuromuscular junction. - Answer Acetylcholine
The gangster movies call a dead person a stiff, rigor mortis is the proper name. How
does this occur? - Answer Without ATP, muscles remain fixed in their last state of
contraction.
Muscle myofibrils ________. - Answer Contain myosin and actin myofilaments.
Troponin ________. - Answer Has a calcium-binding site.
A myofibril is the ________. - Answer Contractile thread that extends the length of
the muscle fiber
Which of the following statements regarding the sliding filament model is false? -
Answer Both actin and myosin myofilaments shorten during contraction.
T tubules are invaginations of the ________. - Answer Sarcolemma
One cause of spastic paralysis might be ________. - Answer Inhibition of
acetylcholinesterase
The striated appearance of skeletal muscle results from the _________. - Answer
Sarcomere organization
A shift in metabolism that breaks down pyruvic acid to lactic acid is called
_________. - Answer Anaerobic threshold
Somatic motor neurons release the neurotransmitter _________ at the myoneural
junction. - Answer Acetylcholine
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