Cardiovascular System Exam

Correct Answer: A

Rationale: The correct answer is the SA node. The sinoatrial (SA) node is known as the natural pacemaker of the heart as it generates electrical impulses initiating each heartbeat. The SA node is located in the right atrium and sets the rhythm and rate of the heartbeat. The AV node (choice B) is responsible for delaying the electrical impulse to allow the atria to contract before the ventricles. Purkinje fibers (choice C) are specialized cardiac fibers responsible for the rapid conduction of impulses to the myocardial cells, and the atria (choice D) are the upper chambers of the heart involved in receiving blood from the veins.

Correct Answer: A

Rationale: The correct answer is A, cystic fibrosis. Cystic fibrosis is a genetic disorder that primarily affects the lungs and digestive system. It leads to the production of thick, sticky mucus that can clog the airways, causing respiratory issues. Choice B, COPD (Chronic Obstructive Pulmonary Disease), is a different condition usually caused by smoking or exposure to irritants. Choice C, bronchiectasis, involves the widening and scarring of the airways, not the production of thick mucus. Choice D, pulmonary fibrosis, is a lung disease characterized by scarring of the lung tissue, not excessive mucus production.

Correct Answer: A

Rationale: When administering furosemide (Lasix), it is crucial to monitor potassium levels closely. Furosemide is a loop diuretic that can lead to potassium loss, potentially causing hypokalemia. Monitoring potassium levels helps prevent adverse effects associated with low potassium, such as cardiac arrhythmias. While monitoring sodium, calcium, and chloride levels may also be important in certain situations, potassium is the most critical to monitor when administering furosemide.

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 to hold the digoxin and notify the healthcare provider. A potassium level of 2.8 mEq/L indicates hypokalemia, which can increase the risk of digoxin toxicity. Holding the medication and informing the healthcare provider is crucial to prevent adverse effects. Choice B is incorrect because increasing the dose of digoxin would further raise the risk of toxicity. Choice C is incorrect as continuing the current dose could exacerbate the toxicity risk. Choice D is incorrect because administering potassium supplements alone is not sufficient to address the potential digoxin toxicity; the first step should be to hold the digoxin and seek further guidance.