Which muscle is also called striated muscle and is responsible for voluntary movements?

Which muscle is also called striated muscle and is responsible for voluntary movements?

• A. Smooth muscle
• B. Skeletal muscle
• C. Flexor
• D. Extensor

Answer: (B)

Skeletal muscle is the type that moves the skeleton, and it has a striped (striated) appearance under the microscope because its sarcomeres create those regular bands. It is under voluntary control, meaning you consciously decide when to contract these muscles via signals from motor nerves in the somatic nervous system. Smooth muscle, by contrast, lacks striations and works automatically in the walls of hollow organs, so it’s involuntary. Cardiac muscle is also striated, but it’s not under conscious control—it beats on its own due to the heart’s intrinsic rhythm. Flexor and extensor describe the action a muscle performs at a joint, not the tissue type, so they’re not the general class of muscle responsible for voluntary movement.

Skeletal muscle is the type that moves the skeleton, and it has a striped (striated) appearance under the microscope because its sarcomeres create those regular bands. It is under voluntary control, meaning you consciously decide when to contract these muscles via signals from motor nerves in the somatic nervous system.

Smooth muscle, by contrast, lacks striations and works automatically in the walls of hollow organs, so it’s involuntary. Cardiac muscle is also striated, but it’s not under conscious control—it beats on its own due to the heart’s intrinsic rhythm. Flexor and extensor describe the action a muscle performs at a joint, not the tissue type, so they’re not the general class of muscle responsible for voluntary movement.