Cardiac Muscle

An illustration of cardiac muscle highlights the unique structure that allows the heart to contract continuously without fatigue. The diagram shows branched muscle fibers connected by intercalated discs, which contain gap junctions and desmosomes. These features allow electrical signals to spread rapidly and keep heart contractions synchronized. Striations similar to skeletal muscle are visible, but the cells are shorter and centrally nucleated. Labels often emphasize the abundance of mitochondria, explaining the heart’s high energy demand. Seeing these features together helps explain why cardiac muscle behaves differently from skeletal and smooth muscle and why it is specially adapted for rhythmic, lifelong activity.