The resistance vessel is ___. ()
A. the large artery
B. the small artery and the arteriole
C. the capillaries
D. the small vein
E. the large vein
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The distribution of sympathetic vasoconstrictor fiber is the densest in the ___. ()
A. large artery
B. arteriole
C. precapillary sphincter
D. venule
E. large vein
The basic cardiovascular center is located in the ___. ()
A. Cerebrum
B. Hypothalamus
C. Midbrain
D. Medulla oblongata
E. Spinal cord
All arteries in the body contain oxygen-rich blood except for ()
A. the aorta
B. the pulmonary artery
C. the renal artery
D. the coronary arteries
E. the liver artery
The first heart sound is produced by closing of the ()
A. aortic semilunar valve
B. the pulmonary semilunar valve
C. the tricuspid valve
D. the bicuspid valve
E. both AV valves
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