CCT - Practice Test || Already Graded A+.

1. Which heart chamber functions to pump deoxygenated blood to the lungs? a. Right atrium b. Right ventricle c. Left atrium d. Left ventricle correct answers 1. B: The right ventricle pumps the deoxygenated blood it has received from the right atrium to the lungs. The right atrium pumps deoxygenated blood from the body to the right ventricle. The left atrium pumps oxygenated blood from the lungs to the left ventricle. The left ventricle pumps oxygenated blood to the body. 2. Which lead is the most affected by respiration? a. V2 b. V4 c. Lead III d. Lead I correct answers 2. C: Lead III is the most affected by respiration, and therefore the waveforms may look different depending on the respiratory cycle. Because of this, a Q wave that only appears in lead III and is not associated with other corresponding changes in other leads is not significant. 3. Which of the following is the correct sequence by which action potentials are conducted through the heart?" a. SA node → AV node → bundle branches → Purkinje fibers b. Bundle branches → Purkinje fibers → SA node → AV node c. Purkinje fibers → SA node → bundle branches → AV node d. AV node → SA node → bundle branches → Purkinje fibers correct answers 3. A: The sequence by which an action potential is conducted through the heart is from the sinoatrial (SA) node to the atrioventricular (AV) node to the bundle branches and then to the Purkinje fibers. 4. What type of heart block is seen in the following electrocardiogram (ECG) strip?" a. First-degree heart block b. Second-degree heart block, type 1 c. Second-degree heart block, type 2 d. Third-degree heart block correct answers 4. B: The pictured ECG is a second-degree heart block, type 1. This rhythm is also called Mobitz I or Wenckebach. With this heart block the PR interval gets longer with each beat until eventually a P wave occurs, but a QRS does not follow (a beat is skipped). After the skipped beat, the pattern starts over again. A first-degree heart block occurs when the PR interval is longer than 0.2 seconds, but the PR interval generally remains constant and the QRS is not dropped. A second-degree heart block, type 2, also called Mobitz II, is apparent when the QRS suddenly fails to show up after a P wave. A fairly consistent ratio of P waves to QRS complexes is common, and this rhythm lacks the increasing PR interval that is seen in the Mobitz I block. A third-degree heart block is also called a complete heart block and the atria and ventricles beat independently of one another.