Beinagrindavöðvi

Beinagrindavöðvi, also known as skeletal muscle, is one of the three major muscle types in the human body, alongside smooth muscle and cardiac muscle. It is a striated muscle tissue, meaning it has a striped appearance under a microscope due to the arrangement of its contractile proteins, actin and myosin. Skeletal muscles are voluntary muscles, meaning their contraction is under conscious control. They are attached to bones by tendons and are responsible for all voluntary movements of the body, such as walking, running, lifting, and manipulating objects.

The structure of skeletal muscle is complex. It is composed of bundles of muscle fibers, which are long, multinucleated cells. Each muscle fiber contains myofibrils, which are filled with repeating units called sarcomeres. The sliding of these sarcomeres past each other, powered by the interaction of actin and myosin filaments, generates muscle force. Energy for muscle contraction is primarily supplied by ATP, which is produced through cellular respiration.

Skeletal muscles are crucial for posture, heat generation, and protecting internal organs. They play a vital role in maintaining balance and stability. Damage to skeletal muscles can result from injury, overuse, or disease, leading to pain, weakness, and loss of function. Regular exercise and proper nutrition are important for maintaining healthy skeletal muscles.