Spot the lie

Exercise and reference answers

Questions

1. False statement

   The AV node normally fires faster than the SA node.

   Statements

   1. The AV node normally fires faster than the SA node.
   2. The SA node has the highest inherent rate of depolarization.
   3. The AV node delays the impulse for about 100 ms.

2. False statement

   S2 occurs at the start of ventricular contraction, before S1.

   Statements

   1. S1 is produced by closing of the atrioventricular valves.
   2. S2 occurs at the start of ventricular contraction, before S1.
   3. S2 is produced by closing of the semilunar valves.

3. False statement

   Ejection fraction is stroke volume divided by heart rate.

   Statements

   1. Cardiac output equals heart rate times stroke volume.
   2. A normal resting heart rate is 60 to 100 bpm.
   3. Ejection fraction is stroke volume divided by heart rate.

Instructions

Two of these three statements are true. Tap the false one.