What type of muscle cell forms the wall of the heart?

The type of muscle cell that forms the wall of the heart is cardiac muscle. Cardiac muscle is unique to the heart and has specific characteristics that enable it to fulfill its function of pumping blood throughout the body. These muscle cells are striated, meaning they have a banded appearance due to the organization of their contractile proteins, much like skeletal muscle. However, unlike skeletal muscle, cardiac muscle cells are involuntary, meaning they cannot be consciously controlled. They are also interconnected through specialized junctions called intercalated discs, which allow for synchronized contractions of the heart muscle.

In comparison, skeletal muscle is under voluntary control and primarily responsible for locomotion, while smooth muscle is found in hollow organs like the intestines and blood vessels, working involuntarily to facilitate movement within these structures. Striated muscle is a broader category that includes both skeletal and cardiac muscle. However, the specific type that defines the heart's structure and function is cardiac muscle. Hence, this choice accurately identifies the muscle type related to the heart's composition.