If the Connection Between the SA Node and AV Node

Question

If the connection between the SA node and AV node becomes blocked,
A) the ventricles will beat faster.
B) the ventricles will beat more slowly.
C) the ventricular beat will remain unchanged.
D) cardiac output will increase.
E) the atria will contract more forcefully.

Accepted Answer

When the connection between the SA node and AV node becomes blocked, the ventricles will start to depolarize at a slower rate, leading to a slower ventricular beat. This is because the AV node acts as a delay in the electrical conduction between the atria and ventricles, allowing time for the atria to contract fully before the ventricles contract. When the connection is blocked, the ventricles will not receive a signal from the SA node to contract, and will instead rely on slower, backup pacemakers to initiate the electrical impulse. This can lead to a slower, less efficient heartbeat.