now do the sam for this one, please don't change the words just add in the correct pages for citations and references.: : The essential system for the heart's rhythmic contractions and efficient pumping of blood is the cardiac conduction system. The cardiac conduction system, which is composed of the SA node, AV node, AV node, AV bundle, bundle branches and Purkinje fibres, control the electrical impulses that precisely coordinate the timing of heart chamber contractions. The electrical system of the heart is responsible for regulating how blood flows through its chambers. The right atrium features the sinoatrial (SA) node, that produces an electrical signal at the start of each heartbeat. The heart's upper chambers, the atria, contract in response to this signal, pushing blood into the ventricles, which are the lower chambers. Because the SA node starts this process, it is also called the heart's natural pacemaker. Since the SA node kicks off this activity, it's often called the heart's natural pacemaker (Amerman, 2019, p. 123). Afterward, the signal heads over to the atrioventricular (AV) node, located right between the atria and ventricles. Just long enough for the ventricles to fill with blood from the atria before they begin to contract, this node retains the signal. In order to ensure that the heart beats in a timely manner, this slight delay is crucial (Amerman, 2019, p. 124). The electrical impulse passes via the bundle of His, which is similar to a highway that div