What is muscle tissue made of

The muscles

A skeletal muscle usually connects two bones together, that is, it moves one of the two bones towards the other. Accordingly, one distinguishes one

  • Muscle origin (the attachment close to the trunk),
  • a muscle belly and
  • a muscle attachment (the attachment remote from the torso).

The muscle is attached to the bone by tendons. A muscle can have not just one but also two (e.g. "two-headed muscle" biceps) or three tendons (e.g. "three-headed muscle" triceps). The muscle itself is embedded in a connective tissue sac (fascia) that is embedded in the Tendons transforms.

Every muscle exercises a certain movement in a certain direction, and several muscles often work together as a muscle group. For every muscle or muscle group there is an opponent who controls the exact opposite movement (e.g. extensor muscles as an opponent to the flexor muscles).

The muscle belly can have a wide variety of shapes (spindle-shaped, triangular, etc.). It consists of the actual muscle cells, which are composed of individual, strictly arranged structural elements:

The smallest unit of the muscle is the so-called Myofibrils. Many myofibrils together form oneMuscle fiberwhich can be up to 15 cm long and up to 100 µm wide. Lots of muscle fibers become tooBundles of muscle fibers summarized. The union of several muscle fiber bundles forms the actual muscle.

Functional unit of the muscle fibers

Skeletal muscle structure © designua

Each muscle fiber is traversed lengthwise by the finest, individual protein threads. There are two different types, actin filaments and myosin filaments. Actin filaments appear light under the microscope, myosin filaments are thicker and darker. Due to their special arrangement, which is at regular intervals, they create the image of horizontal stripes. Each of these sections is called a sarcomere (contractile unit of the muscle). Many sarcomeres in a row form the myofibrils.

The actin and myosin filaments do the actual work of the muscle: They can move against each other and thereby cause the muscle to contract (contraction). The contraction of the muscle eventually leads to movement of the bone attached to the muscle.