Nervous system

Here we come to the mention of nervous system, which performs the role of a conductor in a complex functional ensemble. We already said that the single-celled organism has among other functions also the most important property of excitability. This makes it sensitively reacts to change of external conditions. The higher animals this function has assumed a special system - nervous system. The entire surface of the body and all his internal organs permeated sensitive nerve endings fiber - receptors (from lat. recipio - perceived). The slightest change in external conditions or internal environment is primarily influenced by these devices, specially adapted to the perception of various stimuli. From receptors on the fiber signals fly to the bodies of nerve cells located in the spinal cord and brain, and also in the nearest to the brain formations. On the other, motor fibers of the brain sends the response signals to the different organs. This is the basic law of the nervous system called reflex, which means in Latin "reflection"; remember the word "reflector". In fact, all the actions of our body are a reflection of those or other influences, changes in external or internal environment. The influence of these strumming our nervous system, and depending on the "melody", which thus formed, the body gives the answer. This refers not only to the activities of the organs of the body, but of the whole of our complex mental life, because, as we will see in the conversation 9, the content of our psyche is entirely determined accumulated impressions from the external and internal nature and from the surrounding social environment.
Thus, having developed the function of excitability of nervous system communicates the body with the outside world and along with it combines the activities of all bodies, conducts them. Include in the ensemble and the second conductor - humoral (from the Greek. humor - liquid). The glands secrete into the blood substances-regulators - hormones; in addition, in the tissues of many forms other physiologically active substances involved in the management of the Symphony of life.
Performing a Symphony own life, body and protect it - both in the present and in the future. The first of these is the defense of the organism from pathogenic microbes. Special protective service of the body assumes the defense. Another goal is the survival of the species. This is done by a special system of organs of reproduction, where it produces sex cells and the maturation of a fertilized egg.
Protection of life, the present and the future belongs to the most ancient and fundamental functions of the body, is most similar in animals and plants. Therefore, as we would put them in brackets, refer them once described conductors physiological ensemble. However, these functions are largely subject, of course, our conductors.
The poet U. Whitman, admiring the man, a miracle of nature, wise and completely arranged, wrote:
Gentlemen, look at this miracle!
Whatever the price shall give the buyer is enough.
The earth was preparing a quintillion years, without living beings, without plants. For him continuously and accurately revolved worlds In his head - a comprehensive brain, and underneath are the heroes; Look at the hands and feet, red, black, white - they have such skilled tendons and nerves; They need to expose all that you can see them. Great feeling, burning lives eyes, courage and the will.
Layers chest muscles, spine flexible and neck and more elastic meat, strong figure.
And there, inside, even miracles.
There, inside, the blood flows, the same ancient blood!
The same bright red blood!
There beats strokes heart, where all the passion,
desire, desire, gusts. (Il, in your opinion, is there not, once they are not expressed in
classrooms and living rooms?). Not one person - the father of those who will become
fathers;
In him is the source of States crowded republics
the rich.
It is uncountable eternal life and without them
the incarnation and joy.