Muscles are organs of the human body, which consists of muscle tissue, the ability to contract under the influence of nerve impulses.It is an active member of the musculoskeletal system, enabling the movement of a person when moving in space, breathing movements, maintain balance, phonation, reducing the walls of the internal organs, and others. In the human body - about 600 muscles, their share of the total mass of approximately 30%.Muscles also called skeletal muscle, as they are connected to a skeleton substantially the entire surface thereof.
Build muscle
muscle - a collection of bundles of striated fibers, which are connected to the beams of the first order through the loose connective tissue.Next, the first-order beams are combined into bundles of the second and so on.All these combined connective shell eventually form muscle belly.Between the muscle bundles at the ends of the abdomen are connecting layers, which are attached to the bone by the tendon tissue.Such is the structure of the muscles.With the reduction of the muscle belly is shortened, and the ends come together.At this time, the muscle pulls the bone acting as a lever.So committed all sorts of movements.
Each muscle is a single integral body that has a certain structure, form and function.Each is developed in a special way and has its position in the body.As suggested by the structure of human muscles supplied with nerves and blood vessels.Every movement is carried out by means of several muscles.
Now consider the particular structure of the muscles.Those that act in the same direction and jointly produce a similar effect, called synergists.Those muscles that perform movements opposite direction is called antagonists.For example, the elbow flexes the biceps (biceps), unbend - triceps (triceps).Bending the elbow alternating contraction and relaxation of the flexor and extensor muscles, that is, they act as antagonists.However, static load, for example while holding weights in a horizontal position at arm's length - and the flexors and extensors act as synergists.From this we can conclude that structure eliminates muscle performance of only one function, on the contrary it provides their versatility.Due to the fact that participation in each movement of the muscles of both groups accept, our movements inherent accuracy and smoothness.
By the nature of the basic movements, they carried out, and their effect on joint muscles are divided into the following types:
- lead, the outlet,
- flexors, extensors,
- raises, lowers,
- rotate and others.
There are also facial, breathing and chewing muscles.
distinguish them also in size and shape: they can be long, short and wide.Long muscles are located mainly on the limbs, short - between the vertebrae and ribs, wide - on the trunk.Almost all of them are moved through several joints in producing them while reducing motion.
How do muscles
muscle contraction to perform the role of the bone lever of producing mechanical work.In order for it to carry out the work, it requires energy, which is formed by the decay and oxidation of cells received by the organic matter.Nutrients and oxygen supplies blood to the muscles, it also carries away waste products formed by dissimilation.Long work leads to fatigue and decrease their efficiency.
to keep them in good shape requires regular muscular work, which enhances their blood supply.That in turn leads to an increase in muscle mass.Strong muscles support the body perfectly, preventing the curvature of the spine, the emergence of a stoop.
