Anatomy & Physiology Cardiac #14

Question

Which is the correct sequence of events for the electrical impulses that travel through the heart to facilitate a ventricular contraction?

Answers

  1. Atrioventricular node, atrial contraction, sinoatrial node, bundle of His, purkinje fibers, ventricular contraction.
    • Rationale:

      This is not the correct sequence of events for the electrical impulses that travel through the heart to facilitate a ventricular contraction as the sequence begins in the SA, not the AV, node.

  2. Sinoatrial node, atrial contraction, atrioventricular node, purkinje fibers, bundle of His, ventricular contraction.
    • Rationale:

      The sequence is incorrect as the electrical impulses travel through the bundle of His prior to the purkinje fibers.

  3. Atrioventricular node, atrial contraction, sinoatrial node, bundle of His, ventricular contraction, purkinje fibers.
    • Rationale:

      This is not the correct sequence of events for the electrical impulses that travel through the heart to facilitate a ventricular contraction as the sequence begins in the SA, not the AV, node. In addition, the ventricular contraction is not initiated prior to moving through the purkinje fibers.

  4. Sinoatrial node, atrial contraction, atrioventricular node, bundle of His, purkinje fibers, ventricular contraction.
    • Rationale:

      This is the correct sequence of events for the electrical impulses that travel through the heart to facilitate a ventricular contraction.

Overview

The cardiac conduction system is a group of specialized cardiac muscle cells located in the walls of the heart.

Explanation

Learning Outcomes

The specialized cells located in the walls of the heart send signals to the heart muscle. This signal causes the heart to contract. The main components of the cardiac conduction system are the sinoatrial (SA) node, atrioventricular node (AV) node, bundle of His, bundle branches, and purkinje fibers. The correct sequence of events for an electrical impulse to travel through the heart to facilitate ventricular contraction is as follows: SA node, atrial contraction, AV node, bundle of His, and purkinje fibers leading to a ventricular contraction of the heart muscle.

Test Taking Tip

Consider the structure of the heart to determine the correct choice for this question.

Video Rationale