Cardiovascular System Exam Questions

Correct Answer: A

Rationale: The correct answer is A: Cardiac output. Cardiac output is the volume of blood pumped by the heart per minute. It is calculated by multiplying the stroke volume (the amount of blood pumped out of the heart in each beat) by the heart rate (number of heartbeats per minute). This question specifically asks for the total amount of blood pumped through the circulatory system in a minute, which is represented by cardiac output. Choices B, C, and D are incorrect because stroke volume refers to the amount of blood pumped out of the heart in each beat, end-diastolic volume is the volume of blood in the heart at the end of diastole, and ejection fraction is the percentage of blood pumped out of the heart with each contraction, not the total amount pumped per minute.

Correct Answer: A

Rationale: Refractoriness is the correct term to describe the inability of cardiac cells to respond to a new stimulus while they are still in contraction from a previous stimulus. This period is essential for the heart to complete its contraction and relaxation phases without interference. Excitability refers to the ability of cells to respond to stimuli, not the inability to respond. Contractility is the force of cardiac muscle contraction, and automaticity is the ability of cardiac cells to generate electrical impulses spontaneously, which are not relevant to the described scenario.

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: 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: The correct answer is B, Aortic valve. The aortic valve is a semilunar valve located between the left ventricle and the aorta. It prevents the backflow of blood from the aorta into the left ventricle. The pulmonary valve (choice A) is located between the right ventricle and the pulmonary artery, not in the Valsalva's sinus area. The tricuspid valve (choice C) is situated between the right atrium and right ventricle, and the mitral valve (choice D) is located between the left atrium and left ventricle, making them incorrect choices for this question.