The Two Types Of Muscles
A muscle is a group of cells called fibers, and are generally quite big. One muscle fiber has a large amount of myofibrils, which are muscle proteins in the shape of cylinders. These myofibrils contain two different types of filaments, which run along the axis of the fiber in hexagonal patterns. The two types of filaments are thick and thin filaments. Every thick filament is surrounded by six thin filaments. Both thick and thin filaments are attached to a structure called the Z-line. The Z-line runs perpendicular to the axis of the muscle fiber. The myofibril that connects one Z-line to another is called a sarcomere. On the Z-line is a small tube called the T-tubule, which is also part of the cell membrane. Inside the muscle fiber, between