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 C
Explanation
In the initial 24 hours after burn injury, fluid resuscitation is a critical priority in the management of burn patients. Burn injuries can lead to significant fluid loss, both locally at the burn site and systemically due to increased capillary permeability. Fluid resuscitation aims to restore and maintain adequate intravascular volume, ensuring sufficient tissue perfusion and organ function.
The Parkland Formula is commonly used to guide fluid resuscitation in burn patients. It involves calculating the total volume of fluid needed in the first 24 hours, with a portion given in the initial hours after injury and the remainder given over the remaining hours.
A. Sterile dressing changes (option A) are incorrect because they are important in wound care management for burn patients to prevent infection. However, fluid resuscitation takes precedence within the first 24 hours.
B. Emotional support (option B) is incorrect because it is an essential aspect of burn care, as burn injuries can have a significant psychological impact. While emotional support is crucial for the patient's overall well-being, it may not be the highest priority within the first 24 hours compared to addressing the physiological needs of fluid resuscitation.
D. Range-of-motion exercises (option D) are incorrect because they are important for preventing contractures and maintaining joint mobility in burn patients. However, they are typically initiated after the initial fluid resuscitation phase and wound stabilization.
Therefore, the priority the nurse anticipates within the first 24 hours for a 31-year-old male patient with burn injuries is fluid resuscitation.
Correct Answer is ["18"]
Explanation
Step 1: Convert the patient's weight from pounds to kilograms. 130 pounds ÷ 2.205 (1 pound = 0.453592 kilograms) ≈ 58.97 kilograms
Step 2: Calculate the total dosage of Dobutamine required per hour based on the weight-specific dose. 2.5 mcg/kg/min × 58.97 kg = 147.425 mcg/min
Step 3: Calculate the infusion rate (mL/hr) using the concentration of Dobutamine in the prepared solution. The solution contains 250 mg of Dobutamine in 500 mL, which means there are 250,000 mcg of Dobutamine in 500 mL. To determine the mL/hr, divide the required dosage (147.425 mcg/min) by the amount of Dobutamine in 500 mL (250,000 mcg) and multiply by 500 mL (volume of the solution).
(147.425 mcg/min ÷ 250,000 mcg) × 500 mL ≈ 0.295 mL/min
To get the mL/hr, we convert the rate from minutes to hours (60 minutes = 1 hour):
0.295 mL/min × 60 min/hr ≈ 17.7 mL/hr
Round the answer to the nearest whole number:
Approximately 18 mL/hr of Dobutamine should be administered to the patient.
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