Smooth muscle

Definition

Smooth muscle is a type of involuntary muscle tissue that is found in the walls of internal organs such as the stomach, intestines, and blood vessels. Unlike skeletal muscle, smooth muscle fibers are spindle-shaped and do not have striations.

Related terms

Involuntary muscle: Muscle that operates without conscious control, responsible for essential functions like breathing and digestion.

Striated muscle: Muscle tissue that has repeating sarcomeres, giving it a striped appearance; includes skeletal and cardiac muscles.

Sarcomere: The structural unit of a myofibril in striated muscle, consisting of a dark band and the nearer half of each adjacent pale band