One of the reasons you might struggle to lift a heavy object with your arm fully extended is because
A. in extension, the proximity of Z discs to thick filaments restricts the sliding movement within sarcomeres.
B. full extension results in decreased overlap between thick and thin filaments in the muscle.
C. in that posture, some myosin heads overlap actin in the wrong orientation and tug actin in the wrong direction.
D. motor neurons cannot release as much ACh in that posture.
B
You might also like to view...
Which is not characteristic of the endocrine system?
A. Target cells have hormone receptors B. Long-lasting effects C. Rapid, immediate recovery to prestimulation state D. Hormones are released into the bloodstream E. Slow reaction time
Which of the following correctly describes impact?
A. large force applied over a long period of time B. large force applied over a short period of time C. small force applied over a long period of time D. small force applied over a short period of time
Most postganglionic fibers of the sympathetic nervous system secrete the neurotransmitter __________.
Fill in the blank(s) with the appropriate word(s).
The term systole means
a. closure b. conduction c. contraction d. opening e. relaxation