Correct Answer: C

Rationale: The correct answer is C. After the AV node, the electrical impulse is transmitted to the Bundle of His and then to the Purkinje fibers. This sequence is crucial for the coordinated contraction of the ventricles. Choice A (Purkinje fibers, ventricles) is incorrect because the Purkinje fibers come after the Bundle of His in the sequence of electrical conduction. Choice B (Atria, ventricles) is incorrect because the impulse does not go back to the atria after passing through the AV node. Choice D (Ventricles, Purkinje fibers) is incorrect because the impulse first reaches the Bundle of His before spreading to the Purkinje fibers.

Correct Answer: A

Rationale: Valve replacement is the correct answer because it involves replacing a damaged or diseased heart valve with a prosthetic valve. This procedure is essential for improving blood flow and heart function. Angioplasty (choice B) is a procedure to widen narrowed or obstructed arteries. Stent placement (choice C) involves inserting a mesh tube to help support weak arteries. Bypass surgery (choice D) is a procedure to create new routes for blood flow when arteries are blocked.

Correct Answer: D

Rationale: The correct answer is D: Decreases blood pressure. Calcium channel blockers primarily work by relaxing blood vessels, leading to a decrease in blood pressure. While these medications can have secondary effects on the heart, such as reducing the workload of the heart muscle, the primary effect related to blood pressure regulation. Therefore, choices A, B, and C are incorrect as they do not reflect the primary action of calcium channel blockers on the heart.

Correct Answer: A

Rationale: The correct answer is A, Diastole. Diastole is the phase of the cardiac cycle when the heart muscles relax, allowing the chambers to fill with blood. Choice B, Systole, is incorrect as systole is the contraction phase of the heart when blood is pumped out of the chambers. Choice C, Refractoriness, refers to a period during which the heart muscle is unresponsive to stimuli. Choice D, Automaticity, relates to the heart's ability to generate its own electrical impulses.

Correct Answer: A

Rationale: Goodpasture syndrome is the correct answer. It is an autoimmune disease characterized by the immune system attacking the lungs and kidneys, leading to bleeding in the lungs and kidney failure. Sarcoidosis primarily affects the lungs and lymph nodes, not the kidneys. Wegener's granulomatosis affects the lungs, sinuses, and kidneys, but it is characterized by inflammation of blood vessels. Interstitial lung disease involves scarring of the lung tissue, not direct immune system attacks on the lungs and kidneys.