Which muscles act involuntarily give reasons?

Involuntary muscles include smooth muscles and cardiac muscles. Smooth muscles, found in the walls of internal organs like the intestines and blood vessels, function without conscious control to regulate processes such as digestion and blood flow. Cardiac muscle, located in the heart, also operates involuntarily to ensure continuous blood circulation. These muscles are controlled by the autonomic nervous system, allowing the body to maintain essential functions without requiring conscious effort.