The opening and closing of the heart valves is caused by
A. contraction and relaxation of papillary muscles that pull on heart strings.
B. pressure changes of alternating contraction and relaxation during the cardiac cycle.
C. contraction of the smooth muscle in the walls of the great vessels leaving the heart.
D. action potentials within the cusps of the valves.
B
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If the cells of the SA node failed to function, how would the heart rate be affected?
A) The heart would beat faster because the AV node would be the pacemaker. B) The heart would beat slower because the AV node would be the pacemaker. C) The heart would stop beating because the SA node was not acting as the pacemaker. D) The heart would go into an arrhythmia because the Purkinje fibers would try to be the pacemaker. E) The heart would beat faster because the inherent rate of myocardial depolarization is faster than the SA node pacemaker.
Since most filtered bicarbonate is reabsorbed, where does the bicarbonate come from that is used to compensate for acidosis?
A. Glutamine B. Carbon dioxide C. Carbonic acid D. Glucose
Which statement about general senses is true?
A. General senses involve organs located only in the head. B. General sense organs are used for taste, smell, hearing, equilibrium, and vision. C. General sense organs are not located all over the body and are not used for touch, stretch, heat, cold and pain. D. General senses are simple receptors in the skin, muscles, joints, tendons, and organs.
Which statement comparing action potential and local potential is false?
A. Action potentials are not graded and local potentials are. B. Action potentials are not reversible and local potentials are. C. Action potentials are graded and local potentials are not. D. Action potentials are not decrimental and local potentials are.