______ is to slow heart rate as _____ is to fast heart rate.

______ is to slow heart rate as _____ is to fast heart rate.

a. Tachycardia; bradycardia
b. Bradycardia; tachycardia

Answer: B

During the T wave of the electrocardiogram, the ventricles are

During the T wave of the electrocardiogram, the ventricles are

a. depolarizing
b. repolarizing
c. contracting
d. relaxing
e. both B and D

Answer: E

Intercalated discs serve to transfer _____ from cell to cell.

Intercalated discs serve to transfer _____ from cell to cell.

a. ionic currents
b. action potentials
c. the force of contraction
d. all of the above
e. A and B only

Answer: D

The wall of the left ventricle is thicker than the right because

The wall of the left ventricle is thicker than the right because 

a. the left ventricle does more work than the right ventricle
b. the left ventricle pumps a greater volume of blood than the right ventricle
c. the left ventricle produces a higher pressure than the right
d. both A and B
e. both A and C

Answer: E

The first heart sound is heard when the

The first heart sound is heard when the 

a. AV valves open
b. AV valves close
c. semilunar valves close
d. atria contract
e. blood enters the aorta

Answer: B

The normal pacemaker of the heart is located in the

The normal pacemaker of the heart is located in the 

a. Purkinje fibers
b. SA node
c. AV node
d. wall of left ventricle
e. both left and right ventricles

Answer: B