The removal of calcium ions from the cytosol of skeletal muscle causes
A. the myosin binding sites on actin to be uncovered by tropomyosin.
B. tropomyosin to change conformation and thereby move troponin molecules over cross-bridge binding sites.
C. troponin to change conformation and thereby expose cross-bridge binding sites.
D. the myosin binding sites on actin to be covered by tropomyosin.
E. None of the choices is correct.
D
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The smooth muscle layer of the uterus is called the ________
A) Fundus B) Myometrium C) Endometrium D) Cervix
The functional unit of muscle contraction is
A) the myosin cross-bridge. B) the muscle fiber. C) the muscle. D) the sarcomere.
Which of the following is a function of the heart skeleton?
A. Supplies support and reinforcement for the valves B. Provides a rigid site for cardiac muscle attachment C. Provides electrical insulation between the atria and ventricles D. All of the choices are functions of the heart skeleton.
The dendrites of a neuron interact with several different axon terminals. Some of them are sending excitatory signals, while others are sending inhibitory signals. Over the course of the effects of these signals, the neuronal membrane potential reaches around -90mV. This means, overall, that the neuron will be
A. stabilized to remain at resting potential. B. excited enough to easily cross threshold and generate an action potential. C. inhibited from generating action potentials. D. excited, but not enough to cross threshold.