What is the function of the pacemaker in the heart?

The pacemaker, also known as the sinoatrial (SA) node, plays a critical role in regulating the heart's rhythm. Its primary function is to generate electrical impulses that initiate heartbeats. These impulses spread through the heart muscle, causing it to contract and pump blood effectively. By controlling the sequence and timing of these electrical signals, the pacemaker sets the resting heart rate, ensuring that the heart beats at a pace suitable for the body's demands.

This function is vital for maintaining an adequate blood flow, as it allows for the proper coordination of heart contractions. When the pacemaker sends out electrical signals, they travel through specialized pathways in the heart, leading to the synchronized contraction of the atria and ventricles.

In contrast, the other options refer to functions unrelated to the pacemaker. Hormones regulating blood pressure are produced by other glands, while blood filtration and red blood cell production occur primarily in the kidneys and bone marrow, respectively. The connection between heart valves is managed by different structures within the heart, not the pacemaker itself. Thus, the correct answer highlights the essential role of the pacemaker in maintaining the heart's rhythm and function.