Nokea
Which heart chamber receives oxygenated blood from the four pulmonary veins and serves as a reservoir during ventricular systole?
- A. Right atrium
- B. Left atrium
- C. Right ventricle
- D. Left ventricle
Correct Answer: B
Rationale: The correct answer is B: Left atrium. The left atrium receives oxygenated blood from the pulmonary veins, acting as a reservoir during ventricular systole. This blood is then pumped into the left ventricle for distribution to the body. The right atrium receives deoxygenated blood from the body via the vena cavae. The right ventricle pumps this blood to the lungs for oxygenation. The left ventricle is responsible for pumping oxygenated blood to the rest of the body. Therefore, the left atrium is the correct choice based on its role in receiving oxygenated blood from the pulmonary veins.
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The client is on enoxaparin (Lovenox) for DVT prophylaxis. What is the most important lab value to monitor?
- A. Platelet count
- B. PT/INR
- C. aPTT
- D. Hemoglobin
Correct Answer: A
Rationale: The correct answer is A: Platelet count. Enoxaparin is a low molecular weight heparin that can cause thrombocytopenia, a potentially serious side effect. Monitoring platelet count is crucial to detect any decrease, as it may increase the risk of bleeding. PT/INR and aPTT are used to monitor warfarin and heparin, respectively, not enoxaparin. Hemoglobin monitoring is important for anemia but not the most crucial lab value in this scenario.
Which of the following is a central vasodilator and peripheral vasoconstrictor?
- A. Sympathetic nervous system
- B. Parasympathetic nervous system
- C. Norepinephrine
- D. Acetylcholine
Correct Answer: A
Rationale: The correct answer is A: Sympathetic nervous system. The sympathetic nervous system releases norepinephrine, which acts as a central vasodilator by dilating blood vessels in the heart and skeletal muscles. It also acts as a peripheral vasoconstrictor by constricting blood vessels in other areas to redirect blood flow to vital organs during fight-or-flight responses.
B: Parasympathetic nervous system is incorrect as it primarily promotes rest and digestion, not vasodilation or vasoconstriction.
C: Norepinephrine is incorrect as it acts as a peripheral vasoconstrictor, not a central vasodilator.
D: Acetylcholine is incorrect as it primarily functions in the parasympathetic nervous system and is not associated with central vasodilation or peripheral vasoconstriction.
What condition is characterized by a water hammer pulse?
- A. Aortic regurgitation
- B. Mitral valve stenosis
- C. Mitral regurgitation
- D. Aortic stenosis
Correct Answer: A
Rationale: A water-hammer pulse is characteristic of aortic regurgitation due to the sudden increase in arterial pressure followed by rapid decline.
From where do these originate, behind the cusps of the aortic valve, in an area known as Valsalva's sinus?
- A. Pulmonary valve
- B. Aortic valve
- C. Tricuspid valve
- D. Mitral valve
Correct Answer: B
Rationale: Rationale: The correct answer is B - Aortic valve. This is because Valsalva's sinus is located behind the cusps of the aortic valve. The sinuses of Valsalva are pouch-like dilations found at the root of the aorta, just above the aortic valve. These sinuses are important in preventing backflow of blood into the heart during diastole. The other choices, A, C, and D, are incorrect because they do not originate from Valsalva's sinus. The pulmonary valve is located in the pulmonary artery, the tricuspid valve is between the right atrium and right ventricle, and the mitral valve is between the left atrium and left ventricle.
The nurse is administering enoxaparin (Lovenox) to a client. What is the most important lab value to monitor?
- A. Platelet count
- B. Hemoglobin
- C. White blood cell count
- D. aPTT
Correct Answer: A
Rationale: The correct answer is A: Platelet count. Enoxaparin is an anticoagulant that works by preventing blood clots. Monitoring platelet count is crucial to assess for potential thrombocytopenia, a side effect of enoxaparin that can increase the risk of bleeding. Hemoglobin (B) and White blood cell count (C) are not directly affected by enoxaparin. aPTT (D) is not the most important lab value to monitor as enoxaparin does not directly affect this clotting parameter.