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Author Question: Why is the electrical impulse temporarily delayed at the atrioventricular (AV) node? a. To allow ... (Read 71 times)

ahriuashd

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on: Jul 16, 2018
Why is the electrical impulse temporarily delayed at the atrioventricular (AV) node?
 
  a. To allow complete emptying of the ventri-cles
  b. To allow more sodium buildup in the my-ocardial cells
  c. To allow better filling of the ventricles
  d. To allow complete filling of the atria

Question 2

What structure serves as the backup pacemaker for the heart?
 
  a. Atrioventricular (AV) node
  b. Sinoatrial (SA) node
  c. Bundle of His
  d. Purkinje fibers


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cdmart10

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Reply #1 on: Jul 16, 2018
Answer to Question 1

ANS: C
The impulse is temporarily delayed at the AV node in order to allow the ventricles time to fill with blood. That brief delay also limits the rate of the ventricular stimulation during excessively fast atrial rhythms that, if passed to the ventricles, would lead to inadequate cardiac output.

Answer to Question 2

ANS: A
After leaving the atria, the impulse moves to the AV node, located in the intraventricular septum in the inferior aspect of the right atrium (Figure 18-2). The AV node is the backup pacemaker because it has the second greatest degree of automaticity in the healthy heart.


ahriuashd

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Reply 2 on: Jul 16, 2018
Gracias!

emsimon14

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Reply 3 on: Yesterday
Excellent

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