What is the characteristic appearance of skeletal muscles due to their structure?

Skeletal muscles exhibit a distinctive character due to their unique structure, prominently showcasing striations. These striations are alternating bands of light and dark that reflect the arrangement of myofibrils within the muscle fibers, which are composed of actin and myosin filaments. This striated appearance is a direct result of the precise, organized overlapping of these filaments, allowing for efficient contraction and movement.

Contrasted with other muscle types, such as smooth muscle, which is flat and lacks such striations, or cardiac muscle, which includes some striations but has a different structure and function, skeletal muscles are specifically designed for voluntary movements and generating force in a manner that is visually evident through their stringlike appearance. The mention of other shapes like round and bulbous or long and narrow doesn't accurately capture the critical aspect of the skeletal muscle structure relevant to its function and appearance. The stringlike characteristic specifically points to the striated structure that defines skeletal muscle tissue.