Correct Answer: A

Rationale: The correct answer is the Sympathetic nervous system. The sympathetic nervous system is a branch of the autonomic nervous system that is responsible for the fight-or-flight response. It causes vasodilation in central vessels to increase blood flow to vital organs during stress or exercise, while inducing vasoconstriction in peripheral vessels to redirect blood to essential areas. Norepinephrine and acetylcholine are neurotransmitters associated with the sympathetic and parasympathetic nervous systems, respectively, but they are not themselves central vasodilators and peripheral vasoconstrictors.

Correct Answer: B

Rationale: An INR of 1.5 is below the therapeutic range for a client on warfarin, indicating that the client may be at risk of clot formation. The nurse's priority action should be to hold the next dose of warfarin to prevent further reduction of the INR. Increasing the dose could potentially lead to an increased risk of bleeding, and continuing the current dose may not be sufficient to bring the INR within the therapeutic range. Monitoring the client's INR closely is important but not the priority action in this scenario.

Correct Answer: A

Rationale: A transient ischemic attack (TIA) is the correct answer. A TIA is often referred to as a mini-stroke because it is caused by a temporary blockage of blood flow to the brain. This blockage resolves on its own, typically within minutes to hours, leading to temporary symptoms similar to a stroke. Option B, 'Stroke,' is incorrect because a stroke involves a more prolonged interruption of blood flow to the brain. Option C, 'Aneurysm,' is incorrect as it is a bulge in a blood vessel that can rupture and cause bleeding, not a temporary blockage of blood flow. Option D, 'Myocardial infarction,' is also incorrect as it refers to a heart attack, not a condition involving the brain's blood flow.

Correct Answer: A

Rationale: The correct answer is A: Hypertrophic cardiomyopathy. In this condition, the heart muscle thickens, leading to a decreased ability to pump blood effectively. Choice B, Dilated cardiomyopathy, is characterized by the heart chambers enlarging and weakening. Choice C, Restrictive cardiomyopathy, involves the heart muscle becoming rigid and less compliant. Choice D, Ischemic cardiomyopathy, is when the heart muscle is weakened due to reduced blood flow.

Correct Answer: A

Rationale: Tachycardia is the correct answer because it is a condition characterized by a fast heart rate, which can decrease the heart's efficiency in pumping blood. Bradycardia, on the other hand, refers to a slow heart rate, which is the opposite of what is described in the question. Arrhythmia is a general term for any irregularity in the heart's rhythm, not necessarily specifically related to a fast heart rate. Ventricular fibrillation is a life-threatening arrhythmia where the heart's lower chambers quiver instead of pumping blood effectively, but it is not specifically characterized by a fast heart rate.