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Cardiac muscle is the type of muscle tissue responsible for the involuntary movements in the heart. It is unique in that it combines features of both skeletal and smooth muscle, but it is distinct in its function and structure. Cardiac muscle fibers are striated, much like skeletal muscle, but they operate involuntarily and are not under conscious control, which is a characteristic more aligned with smooth muscle.

The muscle tissue in the heart has specialized cells known as cardiomyocytes, which are interconnected through intercalated discs, allowing for coordinated contractions essential for pumping blood effectively. This involuntary nature enables the heart to function automatically, responding tactically to bodily demands for blood and oxygen without requiring conscious thought.

In contrast, skeletal muscle is typically under voluntary control, allowing individuals to move their limbs and body. Striated muscle, while it can reference both skeletal and cardiac muscle due to the presence of striations, is less specific and does not denote the involuntary contraction characteristic exclusive to cardiac muscle. Smooth muscle, found in various organs and blood vessels, is also involuntary, but it does not play a role in the heart's contractions. Therefore, cardiac muscle is the correct and specific answer regarding the tissue responsible for involuntary movements in the