assignment. the intrinsic ability of cardiac muscle to generate action potentials (APs) rhythmically is achieved by the normal pace maker, the Sino-initial node (S-A node). the S-A node is part of the special excitatory and conductive system of cardiac muscle. with the help of a diagram, describe this conductive system how the AP spreads throughout the muscle.

Question

assignment. the intrinsic ability of cardiac muscle to generate action potentials (APs) rhythmically is achieved by the normal pace maker, the Sino-initial node (S-A node). the S-A node is part of the special excitatory and conductive system of cardiac muscle. with the help of a diagram, describe this conductive system how the AP spreads throughout the muscle.

Answer 1

The conductive system of the cardiac muscle consists of specialized cells that initiate and propagate action potentials (APs) throughout the heart, ensuring coordinated contractions. The main components of this system are the Sinoatrial (S-A) node, Atrioventricular (A-V) node, Bundle of His, bundle branches, and Purkinje fibers. Here is a diagram that illustrates how the AP spreads throughout the muscle:

1. Sinoatrial (S-A) node: The S-A node, located in the upper right atrium, serves as the primary pacemaker of the heart. It generates spontaneous APs, initiating the heartbeat. The APs spread from the S-A node into both atria, causing atrial contraction.

2. Atrioventricular (A-V) node: The APs reach the A-V node, located at the base of the right atrium near the interatrial septum. The A-V node serves as a bridge between the atria and ventricles, delaying the transmission of APs, allowing for atrial contraction to complete before ventricular contraction begins. This delay ensures efficient blood flow.

3. Bundle of His: The APs leave the A-V node and travel through the Bundle of His, which is a specialized electrical pathway that divides into the left and right bundle branches. The Bundle of His conducts the APs rapidly from the A-V node to the ventricles.

4. Bundle branches: The left and right bundle branches extend into the ventricles, transmitting the APs to the Purkinje fibers.

5. Purkinje fibers: The Purkinje fibers spread throughout the ventricles, rapidly conducting the APs throughout the muscle. These fibers ensure synchronous and coordinated contractions of the ventricles, starting from the apex towards the base.

By following this conductive system, the APs spread uniformly throughout the cardiac muscle, leading to efficient and coordinated contractions of the atria and ventricles, enabling proper heart function.