Smooth muscle cells are specialized cells found in various parts of the body, including the walls of organs like the stomach, intestines, and blood vessels. Unlike skeletal muscle cells, which are under voluntary control, smooth muscle cells operate involuntarily, meaning they function automatically without conscious effort. These cells help regulate essential processes, such as digestion and blood flow, by contracting and relaxing in response to signals from the body. These cells are characterized by their spindle shape and lack of striations, which distinguishes them from other muscle types. Smooth muscle cells can contract slowly and sustain their contractions for longer periods, making them crucial for maintaining functions like peristalsis in the digestive tract and controlling blood pressure in the circulatory system.