Final answer:
The AV node is the part of the cardiac conduction system that receives the impulse from the SA nodes and has the slowest rate of firing, which is essential for allowing the atria to empty into the ventricles before ventricular contraction.
Step-by-step explanation:
The correct option : a
The part of the cardiac conduction system that receives the impulse from the SA (sinoatrial) nodes is the atrioventricular (AV) node. The AV node is responsible for receiving the electrical impulses from the SA node, which initiates the contraction of the heart.The cardiac conduction system includes several components that work together to manage the heart's rhythm. When the SA node generates an electrical impulse, it travels through the atria, causing them to contract.
This impulse then reaches the AV node, which briefly delays the signal. This pause is crucial as it allows the atria to completely eject blood into the ventricles. After the delay, the signal proceeds to the atrioventricular bundle (or Bundle of His), then to the bundle branches and finally to the Purkinje fibers, initiating the contraction of the ventricles.It is important to note that out of all the components in the cardiac conduction system, the AV node has the slowest rate of firing. This is by design, as the delay permits the simultaneous ejection of blood from the atria to the ventricles before the ventricles contract.