Which muscle type is located on hollow organs and glands and is involuntary?

• A. Cardiac muscle
• B. Smooth muscle
• C. Ligament
• D. Skeletal muscle

Answer: (B)

Smooth muscle is the muscle type that lines the walls of hollow organs (like the stomach, intestines, bladder, and blood vessels) and surrounds many ducts in glands. It contracts to move contents along the organ or regulate the flow, and it does so involuntarily under autonomic control, not by conscious effort. This contrasts with skeletal muscle, which is voluntary and attached to bones, and cardiac muscle, which is involuntary but located in the heart and has distinct striations and intercalated discs. A ligament isn’t muscle at all; it’s connective tissue that links bones.