Which type of muscle is characterized as specialized and self-stimulating?

Cardiac muscle is characterized as specialized and self-stimulating. This type of muscle is found only in the heart and possesses unique properties that allow it to contract rhythmically and continuously without external stimulation. The muscle cells, or cardiomyocytes, are interconnected through specialized junctions known as intercalated discs, which facilitate coordinated contractions.

The self-stimulating aspect comes from the presence of pacemaker cells, which generate spontaneous electrical impulses that trigger the contractions of cardiac muscle. This inherent ability enables the heart to maintain a steady beat and respond to the body's demand for blood circulation automatically.

While skeletal muscle is under voluntary control and relies on signals from the nervous system for contraction, smooth muscle, found in the walls of hollow organs, is also involuntary and can respond to various stimuli but does not have the same self-stimulating properties as cardiac muscle. Striated muscle refers to both skeletal and cardiac muscles due to their banded appearance, but it is the cardiac type specifically that exhibits the unique features highlighted in the question.