The speed of contraction of skeletal muscle is related to:
A. the oxidative capacity of the skeletal muscle fiber
B. the myosin ATPase activity of the skeletal muscle fiber
C. the level of -adrenergic stimulation
D. the rate of Ca++ extrusion from the skeletal muscle fiber
E. the level of myosin light-chain phosphorylation within the muscle fiber
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Question 2) Malignant hyperthermia is a hereditary disorder that can increase surgical risk, due to elevated temperature during certain types of anesthesia.
The cause of the increased temperature is an increased cytosolic Ca++ level secondary to an anesthetic-induced:
A. increased Ca++ release from the SR, due to a mutation in the ryanodine receptor
B. decreased Ca++ uptake by the SR, due to a mutation in SERCA
C. increased frequency of rupturing of skeletal muscle fibers
D. decreased Ca++ extrusion, due to hyperphosphorylation of the plasmalemmal Ca++ pump
E. increased Ca++ influx, due to a mutation in N-type Ca++ channels
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Question 3) Relaxation of skeletal muscle following contraction requires:
A. Ca++ release by the ryanodine receptor
B. Ca++ uptake by SERCA
C. Ca++ efflux by the plasmalemmal Ca++ pump
D. dephosphorylation of a myosin light chain
E. activation of Rho kinase
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Question 4) Contraction of skeletal muscle in response to an action potential requires:
A. Ca++ influx through L-type Ca++ channels
B. Ca++ binding to troponin C
C. phosphorylation of a myosin light chain
D. phosphorylation of troponin I
E. Ca++ extrusion through the Na+-Ca++ antiporter
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Question 5) In the absence of extracellular Ca++, an action potential in a motor neuron failed to initiate contraction of the innervated skeletal muscle because of:
A. inhibition of Ca++ influx into the innervated muscle
B. inhibition of ACh binding to receptors on the muscle end plate
C. stimulation of ACh degradation
D. inhibition of ACh release from the motor neuron
E. inhibition of Ca++ binding to troponin C in the innervated muscle
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Question 6) The force of contraction of skeletal muscle can be increased by:
A. activating additional skeletal muscle fibers within a motor unit
B. increasing the frequency of action potentials within a skeletal muscle fiber
C. increasing -adrenergic stimulation of the skeletal muscle
D. increasing myosin light chain phosphorylation in the skeletal muscle
E. increasing Ca++ extrusion from the skeletal muscle fiber
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Question 7) Urinary continence is maintained by:
A. excitatory somatic innervation of the internal sphincter
B. excitatory postganglionic parasympathetic innervation of the detrusor muscle
C. excitatory postganglionic parasympathetic innervation of the internal sphincter
D. excitatory postganglionic sympathetic innervation of the detrusor muscle
E. excitatory postganglionic sympathetic innervation of the external sphincter
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Question 8) In a patient with Argyll Robertson pupil, you could expect to find:
A. loss of the accommodation response
B. loss of pupillary constriction when looking at near objects
C. no pupillary response to anticholinergics applied to the affected eye
D. a history of syphilis
E. ptosis
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Question 9) An increase in blood pressure would:
A. stimulate parasympathetic input to the piloerector muscles of the skin
B. inhibit parasympathetic input to the piloerector muscles of the skin
C. stimulate parasympathetic input to the heart
D. stimulate sympathetic input to arterioles in the skin and muscle
E. stimulate sympathetic input to the veins
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Question 10) Klver-Bucy syndrome does not include:
A. visual agnosia
B. hypersexuality
C. hemineglect
D. hyperorality
E. changes in emotional behavior
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