Which type of muscle is specialized for contraction and found in hollow internal organs?

Smooth muscle is specialized for contraction and is primarily found in the walls of hollow internal organs such as the intestines, bladder, and blood vessels. This type of muscle is involuntary, meaning it operates automatically without conscious control. The fibers of smooth muscle are non-striated, providing a more uniform appearance under a microscope compared to the striated pattern seen in skeletal and cardiac muscle.

In contrast, cardiac muscle, while also specialized for contraction, is exclusively found in the heart and is responsible for pumping blood throughout the body. Skeletal muscle is under voluntary control and is primarily attached to bones, allowing for movement of the skeleton. Striated muscle is a term that describes the appearance of both skeletal and cardiac muscle due to their distinct banded patterns, but it does not encompass smooth muscle, which lacks striations. Therefore, smooth muscle is the correct answer for this question regarding hollow internal organs.