myofibrilliä
Myofibrils are the fundamental contractile units of muscle cells, also known as muscle fibers. These long, cylindrical organelles are packed tightly within the sarcoplasm of a muscle cell and are responsible for muscle contraction. Each myofibril is composed of numerous repeating units called sarcomeres.
Within each sarcomere, myofibrils contain two main types of protein filaments: actin and myosin. Actin filaments
Muscle contraction occurs through a process called the sliding filament theory. When a muscle receives a nerve