Functions of AV Node and SA Node

The atrioventricular (AV) node and sinoatrial (SA) node are two important nodes in the electrical conduction system of the heart. These specialized tissues play crucial roles in regulating the heart's rhythm and coordinating the contraction of its chambers.

Sinoatrial (SA) Node:
- The SA node, also known as the pacemaker of the heart, is located in the upper right atrium near the opening of the superior vena cava.
- It initiates the electrical impulses that regulate the heart's rhythm by spontaneously generating action potentials.
- The SA node acts as the primary natural pacemaker, setting the pace for the heart's contractions.
- It generates electrical impulses that travel through the atria, causing them to contract and push blood into the ventricles.
- The SA node ensures that the atria contract before the ventricles, allowing for proper blood flow and efficient pumping.

Atrioventricular (AV) Node:
- The AV node is located in the lower area of the right atrium, near the ventricles.
- It receives the electrical impulses generated by the SA node and serves as a gateway or delay point before transmitting the impulses to the ventricles.
- The AV node delays the electrical signals for a short period, allowing the atria to complete their contraction and fill the ventricles with blood before ventricular contraction.
- This delay is crucial for efficient blood flow and prevents the ventricles from contracting prematurely.
- After the delay, the AV node relays the electrical impulses to the bundle of His, a specialized bundle of fibers that rapidly conducts the impulses to the ventricles.
- The AV node also helps regulate the heart's rhythm by adjusting the speed at which it conducts electrical signals, depending on the body's needs.

Summary:
- The SA node initiates the heart's electrical impulses and sets the pace for its contractions.
- The AV node receives and delays the electrical signals, allowing for efficient blood flow and coordination between the atria and ventricles.
- Together, the SA node and AV node ensure the heart beats in a coordinated manner, pumping blood effectively throughout the body.