Final answer:
The intra-atrial tracts, including Bachmann's bundle, are specialized cells that transmit electrical impulses from the SA node to the AV node, ensuring coordinated atrial contraction. Bachmann's bundle specifically transmits the impulse between the right and left atria.
Step-by-step explanation:
The intra-atrial tracts are specialized conductile cells within the atria of the heart. Their primary role is to transmit the electrical impulses from the sinoatrial (SA) node throughout the myocardial cells of the atrium and to the atrioventricular (AV) node efficiently. The most prominent intra-atrial tract is known as Bachmann's bundle, or the interatrial band, which conducts the impulse directly from the right atrium to the left atrium.
Bachmann's bundle plays a significant role in ensuring the coordinated contraction of the atria, which is crucial for efficient pumping of blood into the ventricles. When the SA node generates an electrical impulse, it rapidly spreads through the atria via these internodal pathways and Bachmann's bundle to reach the AV node. From there, the impulse will travel through the atrioventricular bundle, into the bundle branches, and finally through the Purkinje fibers to stimulate a synchronized contraction of the ventricles.