The normal pathway of the conduction system is which one of the following?
SA node - AV node - bundle of his - bundle branches - Purkinje fibers.
SA node - bundle of his -AV node - bundle branches - Purkinje fibers.
SA node - AV node - bundle branches - Ventricles - Purkinje fibers.
AV node-SA node - a bundle of his - bundle branches - Purkinje fibers.
The Correct Answer is A
This pathway represents the normal sequence of electrical impulses that coordinate the contraction and relaxation of the heart chambers.
The electrical signal originates from the sinoatrial (SA) node, which is often referred to as the natural pacemaker of the heart. It is located in the right atrium and generates the electrical impulses that initiate each heartbeat. From the SA node, the electrical signal travels to the atrioventricular (AV) node, which is located at the junction between the atria and ventricles.
After passing through the AV node, the electrical impulse travels through the bundle of His (also known as the atrioventricular bundle) and divides into the right and left bundle branches. These branches continue the conduction pathway and deliver the electrical signal to the Purkinje fibers.
The Purkinje fibers spread the electrical impulse rapidly throughout the ventricles, stimulating the contraction of the ventricular muscle and allowing for efficient pumping of blood out of the heart.
Therefore, the correct sequence of the normal conduction pathway in the heart is:
A. SA node - AV node - bundle of His - bundle branches - Purkinje fibers.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Systemic vascular resistance represents the resistance to blood flow in the systemic circulation. It is an important indicator of afterload, which is the force against which the left ventricle must pump to eject blood into the systemic circulation. By monitoring the changes in SVR, the nurse can assess the impact of medications aimed at reducing left ventricular afterload.
A. Pulmonary artery wedge pressure (PAWP) in (option A) is incorrect because: PAWP is a measure of left ventricular preload and reflects the pressure within the left atrium and left ventricle at end-diastole. It is not specifically related to afterload reduction.
C. Pulmonary vascular resistance (PVR) in (option C) is incorrect because: PVR represents the resistance to blood flow in the pulmonary circulation. It is not directly related to left ventricular afterload.
D. Central venous pressure (CVP) in (option D) is incorrect because: CVP reflects the pressure in the right atrium and is an indicator of right-sided cardiac function. It is not specifically related to left ventricular afterload reduction.
Therefore, to assess the effectiveness of medications in reducing left ventricular afterload, the nurse should monitor the systemic vascular resistance (SVR).
Correct Answer is D
Explanation
Septic shock is a life-threatening condition characterized by severe infection, systemic inflammation, and inadequate tissue perfusion. Hypotension, as indicated by a low blood pressure reading, is a significant concern in septic shock. It reflects inadequate perfusion to vital organs and tissues, leading to potential organ dysfunction and damage.
While all the assessment data provided may be important and require attention, the low blood pressure (BP) reading indicates impaired systemic perfusion and can contribute to end-organ damage. The nurse should prioritize interventions aimed at improving perfusion and stabilizing the patient's blood pressure.
A. Arterial oxygen saturation is 90% in (option A) is incorrect because While an arterial oxygen saturation of 90% is below the desired range, it is not as immediately life-threatening as low blood pressure. Oxygen therapy and interventions to improve oxygenation should still be initiated, but addressing hypotension takes priority.
B. Urine output of 15 ml for 2 hours in (option B) is incorrect because Decreased urine output is a concerning sign, as it may indicate impaired renal perfusion. However, the immediate concern in septic shock is addressing the low blood pressure to improve overall perfusion, including renal perfusion.
C. Apical pulse 110 beats/min in (option C) is incorrect because: Tachycardia is a common finding in septic shock and represents the body's compensatory response to maintain cardiac output. While it requires monitoring and consideration, low blood pressure is a more significant concern.
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