ATI RN
Cardiovascular System Exam
1. Which fibers distribute the electrical impulse to the ventricles, causing them to contract?
- A. Purkinje fibers
- B. SA node
- C. AV node
- D. Bundle of His
Correct answer: A
Rationale: The correct answer is Purkinje fibers. Purkinje fibers are specialized conducting fibers that distribute the electrical impulse to the ventricles, leading to their contraction. The SA node (sinoatrial node) is responsible for initiating the electrical impulse in the heart, the AV node (atrioventricular node) delays the impulse to allow for proper atrial contraction before ventricular contraction, and the Bundle of His transmits the impulse from the AV node to the ventricles. Therefore, choices B, C, and D are not the correct options for fibers directly distributing the impulse to the ventricles.
2. Which condition is characterized by an inability to effectively pump blood, leading to fluid buildup and swelling in the body?
- A. Heart failure
- B. Cardiomyopathy
- C. Angina
- D. Myocarditis
Correct answer: A
Rationale: Heart failure is the correct answer. It is a condition where the heart is unable to pump blood effectively, resulting in fluid accumulation and swelling in the body. Cardiomyopathy is a disease of the heart muscle that affects its ability to pump blood but is not the specific condition described in the question. Angina is chest pain or discomfort caused by reduced blood flow to the heart, not directly related to fluid buildup and swelling. Myocarditis is inflammation of the heart muscle and does not necessarily involve the inability to pump blood effectively.
3. This term refers to a change in the inotropic state of the muscle without a change in myocardial fiber length.
- A. Contractility
- B. Excitability
- C. Refractoriness
- D. Automaticity
Correct answer: A
Rationale: The correct answer is A: Contractility. Contractility specifically refers to the change in the force of contraction of the heart muscle without changing its length. In this scenario, the focus is on the change in the inotropic state of the muscle, which directly relates to contractility. Choice B, Excitability, refers to the ability of a cell to respond to a stimulus, not specifically related to changes in contractile force. Choice C, Refractoriness, pertains to the period during which a cell is unresponsive to a new stimulus. Choice D, Automaticity, refers to the ability of cardiac cells to spontaneously generate electrical impulses.
4. What is a severe allergic reaction that can cause difficulty breathing and shock?
- A. Anaphylaxis
- B. Asthma attack
- C. Bronchospasm
- D. Hypersensitivity
Correct answer: A
Rationale: Anaphylaxis is the correct answer. It is a severe, potentially life-threatening allergic reaction that can lead to difficulty breathing, low blood pressure, and loss of consciousness. An asthma attack is a separate condition characterized by narrowed airways and difficulty breathing, but it is not necessarily related to an allergic reaction like anaphylaxis. Bronchospasm refers to the sudden constriction of muscles in the bronchi, leading to breathing difficulties, and is not specific to allergic reactions. Hypersensitivity is a general term for an exaggerated immune response to a substance, which may or may not manifest as severe allergic reactions like anaphylaxis.
5. The healthcare provider is preparing to administer heparin to a client. What lab value should be monitored?
- A. PT/INR
- B. aPTT
- C. Platelet count
- D. Hemoglobin
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.
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