What is the Cause of the Striated Appearance of Skeletal

Question

What is the cause of the striated appearance of skeletal and cardiac muscle?
A) the nuclei of the muscle cells
B) the connections of neurons to muscle cells
C) the arrangement of intercalated discs
D) the repeating arrangement of the contractile proteins, actin and myosin
E) the stacking of muscle cells

Accepted Answer

The striated appearance of skeletal and cardiac muscle is due to the repeating arrangement of the contractile proteins, actin, and myosin. This arrangement creates the distinct bands of light and dark that give these muscles their characteristic striped or striated appearance. Other factors, such as the arrangement of intercalated discs in cardiac muscle and the stacking of muscle cells in skeletal muscle, may contribute to overall muscle structure, but they do not create the striated appearance. The nuclei of muscle cells and the connections of neurons to muscle cells are not visible in the striations of these muscles.