What is the average cardiac output?

Correct Answer: B

Rationale: The correct answer is B (Approximately 4 to 8 L per minute) because the average cardiac output in a healthy adult at rest is around 5 L per minute. This range of 4 to 8 L per minute encompasses the typical cardiac output values. Choice A (Approximately 4 to 6 L per minute) is too narrow and excludes the upper range, while Choice C (Approximately 5 to 8 L per minute) is slightly broader but still within the acceptable range. Choice D (Approximately 3 to 7 L per minute) is too low and does not cover the full spectrum of average cardiac output values.

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: C

Rationale: The correct answer is C, the left ventricle. The left ventricle receives oxygenated blood from the lungs through the left atrium and pumps it to the rest of the body via the aorta. This chamber has thicker muscular walls compared to the right ventricle to generate enough force to propel blood throughout the body. The left atrium receives oxygenated blood from the lungs but does not pump blood out to the body. The right atrium receives deoxygenated blood from the body and sends it to the right ventricle, which then pumps it to the lungs for oxygenation. Therefore, choices A, B, and D are incorrect as they do not accurately describe the function of the heart chamber that receives oxygenated blood from the lungs and pumps it to the rest of the body.

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.