The second heart sound, "dup," is caused by the
A. closing of the AV valves.
B. closing of the mitral valve.
C. contraction of the ventricles.
D. closing of the semilunar valves.
Answer: D
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The receptors for dynamic equilibrium are in the ________
A) cochlea B) semicircular canals C) vestibule D) utricle
Which of the following statements concerning action potentials in the heart is correct?
a. The rising phase of the action potential in cardiac autorhythmic cells is due to a rapid Ca2+ influx. b. The rising phase of the action potential in cardiac contractile cells is due to a rapid Na+ influx. c. The plateau phase of the action potential in cardiac contractile cells is due to a slow Ca2+ influx. d. Two of these answers are correct. e. All of these answers are correct.
Which respiratory organ has a cardiac notch?
A) right lung B) left lung C) right primary bronchus D) left primary bronchus E) diaphragm
Substances that can cause birth defects or the death of the embryo are referred to as __________
Fill in the blank with correct word.