As it was done (the end)

We have seen how the evolution winding through trial and error came to the closed vascular system: artery - capillary - Vienna. Such a solution of the task of accelerated progress, when you have already created other homeostatis system has allowed to make rapid progress: now each cell have their own capillary, which ensured its stable environment, regardless of the behavior of other cells. Finally fulfilled a long-standing dream of the old woman-evolution: the ability to build a huge living beings with powerful muscles, and then with a wise brain. We are talking about the higher vertebrates. But while there were only simple chord like lantsetnye, and was a severe setback. For improving all organs and nervous system) you need to develop the achievements in the sphere of circulation, and further progress of the circulatory system demanded the nervous regulation of blood vessels, that is, the spinal cord (and then head) of the brain.
The origin of the brain is not quite clear. We can only say that the spinal cord has arisen not from the nerve nodes (ganglia) ancestors of lantsetnye. But in body mind lantsetnye there are many light-sensitive nerve cells in the eyes of Hesse. They are vital: lunatic lives on the sandy banks, buried to a depth of one-two layers of sand grains. Here he was safe from predators. This is probably enabled it to survive to our days. Eyes Hesse allow the animal to determine how deeply it buried in the sand. Eyes sitting in the trunk brain along its length. They form something very similar to our retina. Oregon (primitive nervous system worm-like ancestors of lanzetta) is the centre for the eyes. Probably, in the future options is changed: what was eye, was the embryo of the Central nervous system, and that was all nervous system (Oregon), was only its peripheral part.
The simplest vertebrates - Cyclostomata (hagfish and lampreys) has spinal cord, thickened at the front. A thickening of the brain. Slim front and thick roots back in each segment of the spinal cord (the General principle of the structure of the Central nervous system of vertebrates) are deprived ganglia inherent in the rest of vertebrate, although supply endings not only the muscles and internal organs. The vagus nerve (brain, double, like all animals "in the future"), mostly sensitive nerve entrails.
Heart of mixin - without nerves. It does not change the frequency of beating for years, but weak summary of bezdarnogo heart increases and strong brakes. The lamprey, higher, vagus heart has a branch, but also, as has been said, without retinal breaks, and irritation of the nerve always calls only increased.
In lower vertebrates vagus spent most sensitive endings Gill region, which is the main reflexogenic zone. Subsequently, landfall, Gill vessels and nerves is converted to a main reflexogenic zones of the circulatory and respiratory systems.
Heart, bone fishes, our great ancestors, has only parasympathetic nervous management, and vagus nerve irritation may be caused by acceleration or slowing of the heart rate depending on the intensity of blood flow. This experience was first staged in the laboratory Weber. A characteristic feature of fishes: and their vagus two centrifugal branches innervates the heart and muscles of the pharynx. Severe irritation vagus above branching stops (stop) the heart and at the same time stimulates the muscles of the pharynx, for pharyngeal branch in contrast to the heart is deprived of retinal break, and here braking impossible, heart branch May slow down.
The lobe-finned fish - latimeria no heart, only the vessels, but the sympathetic ganglia along the spine (not yet fully decorated in a chain) is obvious. With landfall chain becomes continuous, and innervation receptacles, always sympathetic - acquires segmental character. Now you can change the tone of vessels not only as a whole, and selectively. Therefore the opportunity to redistribute the blood, and to withstand the force of gravity, exciting the blood down. Now it is possible to stabilize the temperature of the body, as increased exchange and heat production and heat loss is regulated also by the redistribution of blood flow between deep and surface layers of the body. Actually segmental nervous control of vessels fish not yet implemented; they have reptiles and warm-blooded.
Further improvement of the vegetative nervous regulation - creating a thin nerve fibers conducting excitation of two-three orders of magnitude slower than doing thick axons. Now the nerve impulse reaches the vascular muscles are not simultaneously on all axons, not like a bullet, and multiplied crumbles drum beats, sometimes lasting a second. This is the variance in time, supplementing the above spatial dispersion.
All vegetative nerves get ganglia, where the preganglionarnah neurons convey the excitement postganglionarnyh. The number of interoception is growing like an avalanche, the internal environment of an organism of warm-blooded stabilized all better, and it allows you to create intelligence. The brain is in a stable environment. Now can develop both the author and the reader. Everything is ready. It remains to invent the printing press, and there is close to all of the other wonders of the modern world.