What is straited muscle?

Striated muscle, also called voluntary muscle or skeletal muscle, is one of the three types of muscle in the body, the other two being smooth muscle and cardiac muscle. Striated muscle is responsible for voluntary movement and maintains posture. It is attached to bones by tendons. Under a microscope, striated muscle appears striped, with alternating dark and light bands. These bands are created by the arrangement of actin and myosin filaments within the muscle cells.

Structure of Striated Muscle

Striated muscle is composed of long, cylindrical muscle fibers that are bundled together into fascicles. Each muscle fiber is surrounded by a plasma membrane called the sarcolemma, and the cell's cytoplasm is called the sarcoplasm. The sarcoplasm contains myofibrils, which are the contractile elements of the muscle.

Myofibrils are composed of repeating units called sarcomeres. Each sarcomere consists of a thick filament, composed of myosin, and two thin filaments, composed of actin. The thick and thin filaments are arranged in a hexagonal pattern, with the thick filaments surrounded by the thin filaments.

How Striated Muscle Contracts

When a muscle is stimulated, calcium ions are released from the sarcoplasmic reticulum, a specialized membrane system within the muscle cell. These calcium ions bind to the thin filaments, causing them to change shape and attach to the thick filaments. This attachment forms cross-bridges, which are responsible for the contractile force of the muscle.

The sliding filament theory of muscle contraction states that when a muscle is stimulated, the thin filaments slide past the thick filaments, causing the sarcomere to shorten. This shortening of the sarcomeres results in the contraction of the muscle fiber.

Role of Striated Muscle

Striated muscle is responsible for voluntary movement and maintains posture. It is the type of muscle that is used when you walk, run, lift weights, or type on a keyboard. Striated muscle is also important for maintaining balance and coordination.

Examples of Striated Muscles

Some examples of striated muscles include:

* The biceps brachii, which is located on the front of the upper arm

* The quadriceps femoris, which is located on the front of the thigh

* The gastrocnemius, which is located on the back of the lower leg

* The deltoids, which are located on the shoulders

* The pectoralis major, which is located on the chest