Correct Answer: A

Rationale: Heart block is the correct answer because it specifically refers to a condition where the heart's electrical impulses are delayed or blocked, resulting in a slower or irregular heartbeat. Tachycardia (choice B) is a condition characterized by a fast heart rate, Bradycardia (choice C) is a slow heart rate, and Arrhythmia (choice D) is a general term used to describe any abnormal heart rhythm, which may or may not involve delays or blocks in electrical impulses.

Correct Answer: A

Rationale: The correct answer is A: Pulmonary toxicity. Amiodarone is known for causing serious pulmonary toxicity, which can be fatal. Monitoring for pulmonary toxicity is crucial due to its potential severity. Choice B, thyroid dysfunction, is a common side effect of amiodarone but is not as immediately life-threatening as pulmonary toxicity. Choices C and D, liver toxicity and renal dysfunction, are potential side effects of amiodarone but are not as critical or as common as pulmonary toxicity, making them less important to monitor initially.

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: Automaticity is the correct answer because it refers to the inherent ability of cardiac cells to generate electrical impulses without the need for external stimulation. Contractility (Choice B) is the ability of the heart muscle to contract and generate force, not related to electrical impulse generation. Conductivity (Choice C) refers to the ability of cardiac cells to transmit electrical impulses from cell to cell, not the spontaneous generation of impulses. Refractoriness (Choice D) is the period during which the cardiac cells are recovering and not able to respond to a new stimulus, not the spontaneous generation of impulses.

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.