The muscles are roughly subdivided into the skeletal muscles of the musculoskeletal system, the smooth muscles of the internal organs and the heart muscle.
While skeletal muscles can be arbitrarily controlled with the will, the smooth muscles work largely independently of the intentions of humans. In the digestive system, for example, smooth muscle cells do their work at their own pace and are not influenced by a person's will.
Similarly, it is hardly possible to let the heart beat at will because the heart muscle tissue is also not subject to the will of a person.
The muscles of the locomotor system usually consist of a muscle belly and two tendons, which are usually attached to bones or connective tissue.
Some muscles are also made up of two or more muscle bellies with a corresponding number of tendons. The muscle belly is surrounded by a connective tissue sheath and is divided into numerous bundles of muscle fibers. The core of each muscle fiber is a contracting protein network of mainly three proteins, myosin, actin and troponin.
The actin forms a system of short fibers that resemble the spars of a ladder. In each case between two actin spars, myosin proteins are attached by means of resilient troponin proteins. At the appropriate nerve signal, the myosin proteins on the actin spars climb up like a real ladder and the muscle can shorten.
Heart muscle cells are differentiated from the other muscle types in that they can also feed themselves directly from fats and cholesterol from the bloodstream and generate electrical impulses of their own accord at a certain heart rate and also pass them on cell by cell to all other cells Heart can beat as a whole and coordinated.
Due to the structure of the muscles, a muscle can only shorten or relax. In order to allow a movement of the limbs and the body and the trunk in all directions, the muscles of the musculoskeletal system are each arranged in antagonists.
For example, the two-armed arm muscle is responsible for the flexion in the elbow joint, while the arm muscle with the three muscle bellies executes the extension in the elbow joint as its counterpart. Another peculiarity in the way muscles work is that a muscle rarely performs one task. Most joints are moved in different directions by the same muscle.
Thus, the two-headed arm muscle not only flexes the arm in the elbow joint, it also lifts the arm with his longer muscle belly away from the body or leads him with his shorter body of muscle back to the body. In addition help with the forward swinging of the arm and the rotation of the whole arm inward with. In addition, he is the strongest forearm-twisting muscle.
The smooth muscles, on the other hand, have the function of uniting in the internal organs, including the blood vessels, within the body. One of the peculiarities of smooth muscle cells is that they can not only unite and relax, but can also remain in a united state.
The most common ailments that can occur in the skeletal muscles are muscle hardening, muscle strain along with sore muscles or muscle spasms.
Diseases that can occur in the muscles include a variety of genetic muscle weaknesses such as the Becker syndrome, in which the body can not properly produce an essential protein in the muscle, thereby rendering the muscle inoperative and weak.
Many metabolic diseases or nerve disorders such as paralysis are manifested in the muscles. In addition, there are anti-immune diseases caused by the body's own defense system. The other two types of muscles are affected by other diseases. Inadequate oxygenation can be from heartache to heart attack.