Final answer:
The AV node in the heart delays the transmission of electrical impulses from the atria to the ventricles. A defective AV node can result in heart block.
Step-by-step explanation:
The purpose of the AV node in the heart is to delay the transmission of electrical impulses from the atria to the ventricles. This delay allows the atrial cardiomyocytes to complete their contraction and pump blood into the ventricles before the impulse is transmitted to the ventricles themselves.
If a heart has a defective AV node, it can result in a condition known as heart block. Heart block occurs when the electrical signals are blocked or delayed as they pass through the AV node. Depending on the severity of the block, it can affect the heart's ability to pump blood effectively and may require medical intervention.