Which type of muscle is involuntary and found in the walls of hollow organs?

Smooth muscle is indeed the type of muscle that is involuntary and found in the walls of hollow organs. This muscle type plays a crucial role in various bodily functions, such as digestion and blood flow, by contracting and relaxing without conscious control. It is characterized by its non-striated appearance and can be found in places like the intestines, blood vessels, bladder, and uterus.

In contrast, skeletal muscle is under voluntary control and is involved in moving bones and maintaining posture; it has a striated appearance due to its organized arrangement of muscle fibers. Cardiac muscle, while also striated, is specific to the heart and functions involuntarily, but it is not found in the walls of other hollow organs. Striated muscle refers to skeletal and cardiac muscle, both of which exhibit certain organized banding patterns, differing from the smooth muscle's appearance. Thus, smooth muscle is uniquely positioned to perform essential functions in various hollow organs throughout the body.