Vascular reflexes as they are

Will check whether the behavior of blood vessels and the heart to what happens in the autonomic nervous system. It has the sympathetic and parasympathetic divisions. The second consists, first, of wandering nerve, the core of which in the medulla. Another Department parasympathetic system is sacral. The parasympathetic system innervates the heart and smooth muscles of internal organs. Vagus - only autonomic nerve with no segmental device. Parasympathetic ganglia, where synaptic transfer of excitation from the preganglionarnah neurons to postganglionarnyh, are innervated by the authorities or near them. Vessels vagus not innervates.
Reflex arc parasympathetic systems are more complex than somatic: in the first two instead of one neuron centrifugal. The same thing we find in the sympathetic system, which innervates not only internal, but also all the vessels. This system of segmentary, her nerves out of the eighteen segments of the spinal cord and have synaptic break in the ganglia edge of the trunk (the sympathetic chain, walking on the sides of the spine) or in a separate ganglia, which lies a little further - dvuhmetrovy Central path.
The autonomic nervous paths lead to different glands of internal secretion: the hypothalamus part of the brain, pituitary gland, adrenal glands, and other. Reflexes may be stuck at different levels: in the ganglia, spinal cord or brain stem.
When we irritated cat epicardial with increasing force, blood pressure is growing at a weak irritation and falls under strong (forming right camel hump; working point the cat under General anesthesia in the saddle between humps). What's going on in the sensitive nerves of the heart? To sum electrodes under the peripheral segment nerve branches of the heart. It turns out that reflex reaction vessels, heart and respiratory irritation heart depend on subtle, slow-conducting excitation heart afferents and mainly from the initial changes in the electrical activity of these neurons, "initial flash." Mathematical calculation of the energy generated at the moment of explosion, shows that energy is regularly increases proportional to the logarithm of the concentration of nicotine and blood pressure regularly writes camel humps.
Now let's sum more electrodes under the Central segment of the nervous sprigs vascular region and see at the same time, the behavior of centrifugal nerves of different vessels.
In different nerves impeccable direct expressing dependence of the energy of flash from the logarithm of the power of irritation, transformed before our eyes in the curves of different shapes, always contain one or even two hump, while the second is often "incomplete" and curve has the form of the Latin "S". If you compare these curves with curves expressing the change in hydraulic resistance of the relevant vascular zones, in many cases, the curves are similar, although some have a slightly different form.
And should they be the same? The match would mean that the centrifugal impulses to receptacles and the hydraulic resistance change the same and that the sympathetic ganglia passively miss command signal to the smooth muscles. Why are all these ganglia?
But the exact proportion between the receptor activity and the logarithm of their irritation in full accordance with the law of the Weber-Fechner proves: heart receptors faithfully perform their duty, not being indicators, and these measures irritation.