Cardiovascular System Exam

Correct Answer: A

Rationale: The correct answer is A: Right atrium. The right atrium is the heart chamber that receives deoxygenated blood returning from the body via the superior and inferior vena cava. The blood enters the right atrium from the vena cava and then passes through the tricuspid valve into the right ventricle. Choices B, C, and D are incorrect because the left atrium receives oxygenated blood from the lungs, the right ventricle pumps blood to the lungs for oxygenation, and the left ventricle pumps oxygenated blood to the body.

Correct Answer: A

Rationale: Atherosclerosis is the correct answer. It is a condition characterized by the hardening and narrowing of arteries supplying blood to the heart due to plaque buildup. This condition increases the risk of heart attacks. Choice B, aneurysm, refers to a balloon-like bulge in an artery, not the hardening and narrowing of arteries. Choice C, arrhythmia, is an irregular heartbeat and not related to arterial hardening. Choice D, peripheral artery disease, involves the narrowing of arteries that supply blood to the limbs, not specifically to the heart.

Correct Answer: A

Rationale: The correct answer is Purkinje fibers. Purkinje fibers are specialized conducting fibers that distribute the electrical impulse to the ventricles, leading to their contraction. The SA node (sinoatrial node) is responsible for initiating the electrical impulse in the heart, the AV node (atrioventricular node) delays the impulse to allow for proper atrial contraction before ventricular contraction, and the Bundle of His transmits the impulse from the AV node to the ventricles. Therefore, choices B, C, and D are not the correct options for fibers directly distributing the impulse to the ventricles.

Correct Answer: C

Rationale: The correct answer is C. When caring for a client on digoxin with a low potassium level, the priority nursing intervention is to check the digoxin level. Low potassium can increase the risk of digoxin toxicity. Checking the digoxin level will help determine if any adjustments to the medication regimen are needed to prevent potential harm. Choice A is incorrect as a potassium level of 2.5 is low, not normal. Choice B is not the priority as simply giving potassium may not address the underlying issue of potential digoxin toxicity. Choice D is not the initial action to take without assessing the digoxin level first.

Correct Answer: A

Rationale: The PR interval measures the time it takes for the electrical impulse to travel from the atria to the ventricles. It is crucial in diagnosing heart rhythm disorders, as abnormalities in this interval can indicate conduction abnormalities between the atria and ventricles. Choices B, C, and D are incorrect. The QRS complex represents ventricular depolarization, the QT interval represents the duration of ventricular repolarization, and the ST segment represents the time between ventricular depolarization and repolarization.