What tissue primarily composes the heart muscle?

• A. Cardiac muscle tissue
• B. Skeletal muscle tissue
• C. Smooth muscle tissue
• D. Nervous tissue

Answer: (A)

The heart muscle is made primarily of cardiac muscle tissue. This tissue is specialized for rhythmic, involuntary contractions that keep the heart beating. Cardiac muscle cells are striated like skeletal muscle, but they are shorter, branched cells connected by intercalated discs with gap junctions and desmosomes. These connections let ions pass quickly and coordinate contraction across the whole heart—forming a functional syncytium. The heart relies on abundant mitochondria and aerobic metabolism to sustain continuous activity and is modulated by the autonomic nervous system but contracts due to its own intrinsic conduction system. Skeletal muscle tissue is voluntary and attaches to bones; smooth muscle tissue is non-striated and lines hollow organs and vessels; nervous tissue consists of neurons and glia for signaling, not contracting muscle.