Smooth Muscle | Structure and Excitation contraction coupling | BRS Physiology

Smooth muscles are non-striated, involuntary muscles found in the walls of hollow organs such as blood vessels, the digestive tract, the bladder, and the uterus. They are composed of spindle-shaped cells with a single nucleus and lack the organized sarcomeres seen in skeletal muscles. Smooth muscles contract slowly and rhythmically, allowing for functions like regulating blood flow, moving food through the digestive system, and controlling organ emptying. Their activity is controlled by the autonomic nervous system, hormones, and local signals, making them essential for maintaining involuntary bodily functions.