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

Smooth muscle is the type of muscle that is involuntary and found in the walls of hollow organs. This includes structures such as the intestines, blood vessels, bladder, and stomach. Unlike skeletal muscle, which is under conscious control and is striated in appearance, smooth muscle fibers are non-striated and function autonomously. This means they work without conscious effort, allowing for the automatic regulation of functions like digestion and blood flow.

Smooth muscle contractions are typically slow and sustained, allowing for the gradual movement of substances through the hollow organs it lines. This involuntary nature is essential for maintaining vital processes within the body without requiring conscious thought or effort.