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: 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: Pulmonary hypertension is a condition characterized by the thickening and stiffening of the arteries in the lungs, resulting in elevated blood pressure in the pulmonary arteries. This condition is distinct from the other choices provided. Pulmonary fibrosis involves scarring of lung tissue, pulmonary embolism is a blockage in the pulmonary artery, and pulmonary edema is the accumulation of fluid in the lungs.

Correct Answer: A

Rationale: The correct answer is A: Peripheral artery disease (PAD). PAD is a condition where the arteries in the legs or arms become narrowed or blocked, leading to pain and mobility issues. Choice B, Atherosclerosis, refers to the buildup of fats, cholesterol, and other substances in and on the artery walls, not specifically the narrowing or blockage in the extremities. Choice C, Raynaud's disease, is characterized by reduced blood flow to the extremities, leading to coldness, numbness, and color changes in the skin, but it is not primarily about narrowed or blocked arteries. Choice D, Varicose veins, involves enlarged, twisted veins usually in the legs, but it is not related to narrowed or blocked arteries causing pain and mobility issues.

Correct Answer: A

Rationale: The correct answer is A, lung biopsy. A lung biopsy involves removing a small sample of lung tissue for examination under a microscope to diagnose lung conditions. Choice B, bronchoscopy, is a procedure where a thin, flexible tube with a light and camera is inserted into the airways to view the lungs. This procedure is more for diagnostic purposes and not specifically for tissue removal. Choice C, thoracentesis, is a procedure to remove fluid from the pleural space around the lungs for diagnostic or therapeutic purposes, not for tissue biopsy. Choice D, lobectomy, is a surgical procedure to remove a lobe of the lung, usually done to treat conditions like lung cancer or severe infections, but it does not involve removing tissue for microscopic examination.