Cardiovascular System Exam Questions And Answers

Correct Answer: A

Rationale: Anticoagulants are medications specifically designed to prevent blood clots by thinning the blood. They work by interfering with the body's blood clotting process. Beta-blockers, ACE inhibitors, and calcium channel blockers are medications used for different purposes such as managing blood pressure, heart conditions, and regulating heart rhythm, respectively. However, they do not have the primary function of preventing blood clots like anticoagulants.

Correct Answer: B

Rationale: The correct answer is B: Approximately 4 to 8 L per minute. Cardiac output is defined as the volume of blood the heart pumps per minute, typically ranging between 4 to 8 liters. Choices A, C, and D provide ranges that are either too narrow or outside the standard average values for cardiac output, making them incorrect.

Correct Answer: B

Rationale: The correct lab value that should be monitored when administering heparin is the aPTT (activated partial thromboplastin time). Heparin affects the intrinsic pathway of the coagulation cascade, and aPTT is a sensitive measure to assess the effectiveness of heparin therapy. Monitoring aPTT helps in adjusting the heparin dose to maintain the desired anticoagulant effect. PT/INR is more specific to monitor warfarin therapy, not heparin. Platelet count and hemoglobin levels are important parameters to assess bleeding tendencies and oxygen-carrying capacity but are not directly related to monitoring heparin therapy.

Correct Answer: C

Rationale: The correct answer is C. After the AV node, the electrical impulse is transmitted to the Bundle of His and then to the Purkinje fibers. This sequence is crucial for the coordinated contraction of the ventricles. Choice A (Purkinje fibers, ventricles) is incorrect because the Purkinje fibers come after the Bundle of His in the sequence of electrical conduction. Choice B (Atria, ventricles) is incorrect because the impulse does not go back to the atria after passing through the AV node. Choice D (Ventricles, Purkinje fibers) is incorrect because the impulse first reaches the Bundle of His before spreading to the Purkinje fibers.

Correct Answer: A

Rationale: The correct answer is A, Frank-Starling's Law. This law explains that within physiologic limits, the greater the stretch of myocardial fibers, the more forceful the ventricular contraction, leading to an increased stroke volume. Choice B, Automaticity, refers to the ability of cardiac cells to spontaneously generate electrical impulses. Choice C, Contractility, represents the intrinsic ability of the heart muscle to contract. Choice D, Excitability, refers to the ability of cardiac cells to respond to electrical stimuli.