Smooth muscle is a type of involuntary muscle found in various organs throughout the body. Unlike skeletal muscle, which is under conscious control, smooth muscle operates automatically. It is responsible for movements in structures such as the digestive tract, blood vessels, and respiratory system. Smooth muscle cells are spindle-shaped and have a single nucleus. They contract slowly and can sustain contractions for longer periods compared to other muscle types. This allows them to perform essential functions, such as regulating blood flow and moving food through the digestive system, without requiring constant nerve signals.