What characterizes cardiac muscle?

Cardiac muscle is specifically characterized by its unique structure and function, which includes being rugged and specialized for the continuous and rhythmic contractions necessary for pumping blood throughout the body. This muscle type is found exclusively in the heart and is differentiated from other muscle types by its striated appearance and the presence of intercalated discs, which enable rapid communication between the heart muscle cells.

Additionally, cardiac muscle is involuntary, meaning that it operates without conscious control, and it has a unique ability to contract rhythmically and continuously throughout a person’s life. Other options presented describe muscle types that do not accurately capture the specific characteristics of cardiac muscle, which is why they do not align with its properties. Specifically, options describing voluntary muscle or skeletal muscle pertain to different types of muscles with distinct functions and control mechanisms.