Any our action - a touch to a nose tip, walking, acrobatic number - depends on improbably difficult interaction of muscles, a brain and corresponding sites of nervous system.
When muscles of the person co-operate harmoniously and effectively, we say that at it good coordination of movements. People with good coordination, as a rule, carry out movements easily and without visible efforts, as, for example, the sportsman-Olympian. However coordination is necessary not only in sports. Each our movement depends on it.
To execute any co-ordinated movement, whatever simple it was, we should know, how parts of our body settle down in space and correspond with each other. The information necessary for drawing up such "mental cards", arrives through eyes, the balance device in an internal ear and a skin. Sense organs inform us on position and a condition of muscles and joints.
Control center - a brain
We not always realise that performance of such daily actions as drink from a cup, includes two various kinds of activity - intellectual and physical. But before any movement will be executed, there should be a desire (the strong-willed certificate) and the necessary information.
The Area of a brain which is responsible for giving of a signal to action, is called predvigatelnoj (premotornoj), and that which is responsible for its corresponding performance - impellent. Signals thanks to which the spatial perception is carried out, arrive in a parietal share in the top part of a brain; having received therefrom the information, the impellent area gives a command to brush and hand muscles to lift a cup and to bring it to a mouth when you have decided to take a sip. Then the impellent area puts in action a number of other muscles which give the chance to us to involve in itself and to swallow a liquid.
During performance of a series of movements, from the nerves which are in muscles and joints, in a brain the information on continuously arrives in what position and a condition there are these muscles - reductions or relaxations. To take in hands a cup, you slightly move forward, thus the center of gravity of your body is displaced. Reflex mechanisms of balance thanks to which muscles make necessary changes there and then join. Such adaptable changes are regulated by a cerebellum.
For performance of any movements interaction of various groups of muscles is necessary. In muscles there are sensitive fibres, or "spindles" which continuously measure pressure level in muscles and send corresponding signals to a brain through the central nervous system.
Larger sensitive fibres, nervnosuhozhilnye spindles, are in junctions of muscles and sinews. It is considered that they protect the muscles which are at present in work, from a trauma, without allowing impellent impulses to reach a muscle in the event that it is excessively stretched.
The Result of the difficult work connected with management by all muscles, involved in performance of any movement, depends on impellent nervous fibres. They reach for muscles from a brain and a spine column. Each fibre has the branches going to certain group of muscular fibres. When from branches of a nervous fibre the impulse arrives, work is entered by all group of muscular fibres operated it. Such groups of muscular fibres are called as muscular knots. The quantity of muscular fibres in knot depends on accuracy of carried out movement. For example, movements of an eyeball demand very much a split-hair accuracy, therefore in its muscles of all about ten muscular fibres on each muscular knot, and in bicepses (hand muscles) where so it is not required to a split-hair accuracy, each knot totals over thousand muscular fibres.
How muscles carry out actions, partially depends on the information which they constantly receive from the sense organs supervising our movements. The importance of such feedback proves to be true experiments: the person ask something to write, thus the hand he sees only on the TV screen. While the image on the screen completely coincides with how the person usually sees and perceives movements of the hand, he writes how and always. However, it is necessary to change position of the chamber and to show to the person his hand from the unusual party for it as its perception is broken and to write begins very difficultly.
As though well brain and the central nervous system operated work of muscles, and whatever exact were we "mental cards" if muscles are insufficiently developed, we cannot carry out the elementary actions properly. All muscles are formed by a living tissue, and their condition depends on that, it is how much good from blood nutrients and oxygen arrive and ability to live products are deduced.
Walking is a skill it is necessary for them to study, though after the person masters it, he ceases even to reflect on it. Before to rise on feet, the baby should learn to turn over, creep and sit: then it widely places legs to keep balance, and does the first steps. As to the child all is possible to keep balance better and better, it passes to performance of more difficult problems - learns to run, jump and avoid collision with subjects. Throughout all life it masters more and more difficult variants of the basic way of movement.