Which of the following is a central vasoconstrictor and peripheral vasodilator?

Correct Answer: D

Rationale: The correct answer is D: Epinephrine. Epinephrine acts as a central vasoconstrictor by constricting blood vessels in vital organs to redirect blood flow to muscles during fight-or-flight response. It also acts as a peripheral vasodilator by dilating blood vessels in skeletal muscles to increase oxygen delivery. Parasympathetic nervous system (A) mainly promotes relaxation, sympathetic nervous system (B) typically causes vasoconstriction, and dopamine (C) has limited vasoactive effects.

Correct Answer: A

Rationale: The correct answer is A: Diastole. Diastole refers to the relaxation phase of the heart, allowing the chambers to fill with blood. During diastole, the ventricles are relaxed, and blood flows into them from the atria. Systole, choice B, is the contraction phase where the heart pumps blood out. Refractoriness, choice C, refers to the period when the heart cannot respond to a new stimulus. Automaticity, choice D, is the ability of the heart to generate its own electrical impulses. So, diastole is the correct term for the relaxation phase of the heart where chambers fill with blood, making it the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Coronary artery bypass graft (CABG). This procedure involves diverting blood flow around a blocked artery using a healthy blood vessel from another part of the body. It is the most effective treatment for severe coronary artery disease. Angioplasty (B) involves opening a blocked artery with a balloon, stent placement (C) involves inserting a mesh tube to keep an artery open, and valve replacement (D) is for replacing damaged heart valves, not restoring blood flow to the heart.

Correct Answer: A

Rationale: The correct answer is A: Coronary artery disease. This condition involves the narrowing of arteries supplying blood to the heart due to plaque buildup. Plaque can lead to blockages, causing heart attacks and strokes. Peripheral artery disease (B) affects arteries outside the heart. Aortic stenosis (C) is the narrowing of the aortic valve, not arteries. Mitral valve prolapse (D) is a condition affecting the mitral valve, not arteries. Therefore, A is the correct answer.

Correct Answer: A

Rationale: Spirometry is the correct answer because it measures the volume of air exhaled in a specific time frame, assessing lung function and capacity. It is commonly used to diagnose conditions like asthma and COPD. Peak flow meter measures only the maximum speed of exhalation, not volume. Lung volume test measures the total lung capacity, not the speed of air movement. Arterial blood gas measures oxygen and carbon dioxide levels in the blood, not lung function.