What differentiates cardiac muscle from smooth muscle?

• A. Cardiac Muscle Is Only Found In The Heart, And Smooth Muscle Is Found Elsewhere.
• B. Smooth Muscle Is Voluntary, And Cardiac Muscle Is Involuntary.
• C. Cardiac Muscle Is Found In All Major Organs, And Smooth Muscle Is Not.
• D. Smooth Muscle Has Visible Stripes, And Cardiac Muscle Does Not.

Answer: (A)

The key difference is where the tissue is located. Cardiac muscle is found only in the heart, while smooth muscle lines the walls of hollow organs and blood vessels throughout the body. This distribution is the most fundamental way these two muscle types differ. Cardiac muscle is striated and functions involuntarily in the heart, whereas smooth muscle is non-striated and also acts involuntarily in various organs. The other statements mix up location and structural features (for example, the heart’s muscle does have visible stripes, and both types are involuntary), but the defining contrast is the heart-specific presence of cardiac muscle versus smooth muscle’s widespread occurrence.