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

Smooth muscle is the correct answer because it is an involuntary muscle type that operates without conscious control, primarily found in the walls of hollow organs such as the intestines, blood vessels, and the bladder. Its function is to facilitate various involuntary actions, including the movement of food through the digestive system and regulating blood flow in the circulatory system. This muscle type is characterized by its non-striated appearance, which differentiates it from skeletal and cardiac muscles.

Skeletal muscle, on the other hand, is a voluntary muscle that is attached to bones and responsible for moving the skeleton at our will. Cardiac muscle, while also involuntary, is specific to the heart and has a unique structure and function suited to pumping blood. Striated muscle refers to the banded appearance of both skeletal and cardiac muscles, indicating the presence of regular patterned filaments, but does not describe a muscle type that is solely involuntary or located in the walls of organs.