What type of cell is responsible for generating rhythmical electrical impulses in the heart?

The generation of rhythmical electrical impulses in the heart is primarily the responsibility of intrinsic conduction cells. These specialized cells make up the heart's conduction system, which includes structures such as the sinoatrial (SA) node, atrioventricular (AV) node, bundle branches, and Purkinje fibers. The SA node, often referred to as the natural pacemaker of the heart, initiates electrical impulses that trigger heartbeats.

Intrinsic conduction cells have unique properties, including automaticity and excitability, allowing them to spontaneously generate action potentials. This automatic generation of impulses is crucial for maintaining the heart's rhythm and coordinating contractions throughout the cardiac cycle, ensuring efficient blood flow.

In contrast, cardiac muscle cells, or myocardial cells, are responsible for the actual contraction of the heart muscle but do not generate impulses on their own. They respond to the signals initiated by intrinsic conduction cells. Endocardial cells line the inner surface of the heart but do not participate directly in impulse generation or conduction. Thus, the correct answer highlights the specialized role of intrinsic conduction cells in the heart's electrical activity.