In a dream triangle

Well now, the reader, so we, walking in the ways of physiology, moving back and forth, we reached the XX century.
In 1900 in Italy, a physiologist Pagano and independently of him another researcher, Siciliano discovered a mysterious phenomenon.
If you turn your head to the right ninety degrees and slightly downward, to the left on the neck is possible to feel the sternum-lucidnation muscle that connects the mastoid process, the temporal bone behind the ear, with the breastbone and the collarbone. Because of the sternum, as we know, comes the trachea, which together with the previously mentioned muscle forms an angle; this angle is based on the left half of the lower jaw I. the result is a triangle - it surgeons called sleepy triangle, because here is undergoing carotid artery. This artery, reaching the top side of the triangle is divided into two branches: one of these branches nourishes the brain, entering into the cranial cavity and the second; remaining outside the cavity that supplies blood to the outer tissue of the head. These two arterial branches are called respectively the internal and external carotid arteries in contrast to their parent stem, called the common carotid artery. The brain, however, receives blood not only of the internal carotid, but of the vertebral arteries, which throughout go in the bone channel, and there is no sound out.
Both studies Italian scientists are rather close in content to consider them as one. The researchers found that the clamping of the common carotid artery leads to immediate increases in systemic blood pressure - is the opposite of what happens when clamped both branches of the carotid artery when the pressure drops. Together with arterial pressure changes in the heart rate. For this reason Pagano, Siciliano came to the correct conclusion that all perturbations in the body in response to different ways of clamping of the carotid arteries are the reflex and the "entrance gate" is the area of the bifurcation of the common carotid artery on the inside and the outside, and not bleeding of the brain, as it was thought some physiologists. Not bleeding of the brain, for tubal vertebral arteries do not affect blood pressure. Pagano expressed great idea: reflexogenic zone in the area of bifurcation of the carotid artery is a kind of guard, protecting the most vulnerable parts of the body (brain) from the harmful effects of increases in blood pressure. Article Pagano was even said: "nervous guard". But no one has ever seen any of the nerves that come into the area of bifurcation of carotid (so pompously called in the academic world bifurcation of the carotid arteries). Obviously, because this work Siciliano and Pagano was left without attention, and were forgotten by almost a quarter century. New interest in the field of bifurcation carotid broke out in 1923 and is connected with the name of Professor Hering from Cologne.
Professor Goering with its employees Koch, Mies and other primarily found that to the place of bifurcation of the carotid artery comes very thin (and probably because not noticed until that time anatomists nerve, called the sinus nerve or nerve Goring. Why sine? Yes, because in this place of the internal carotid artery is a small short extension that morphological has long called carotid sinus, sinus medicine has not the same meaning as in trigonometry, and means cavity).
Carotid sinus - a kind of gauge to arterial blood. In the laboratory of Goering was established that electric sinus irritation of nerve leads to lower blood pressure and a reduction in the frequency of cardiac contractions, in other capture, sine nerve functioned quite a similar way already known to us, the nerve roots.
Goering, summing up its research and works of Zion and Ludwig with nerve-depressant, and came to the understanding that showed in his opinion, the origin of hypertension. He imagined a system of four nerves (two nerves-depressors and two sine nerves) as a system that regulates blood pressure. In case of any damage to this system should weaken depressant (lowering the pressure in the arteries) reflexes, and resulting in rising pressure level, consistently hampered by this system. Based on such representations (that is, in essence, on the representation of Zion and Ludwig, supplemented in connection with the opening of the sine nerves), the laboratory staff Goering tried to play on the animal such reflexogenic hypertension. This was severed nerves Ziona on both sides. To prevent restore conductivity of these nerves, physiologists removed available as part of each of these two nerve trunks. Then we had to generirovanie and carotid sinus, they acted more decisively - simply deleted.
The reader will probably be surprised: it is known that the carotid artery and therefore are called carotid that if they pinch, the person loses consciousness. It is true, however, this applies primarily to the individual and not to the animals, in which the brain is richly supplied with blood and through the vertebral arteries, and they, for example, for the rabbit to do this is quite wide. Tubal both common carotid arteries, perhaps, and delivers the animal some discomfort, but the behavior rabbit not to determine.
It was expected that after surgery, blood pressure rabbit would instantly jump. This has not happened. Only a couple of weeks the animals became hypertensive patients. Why only two weeks - it is not clear today. All this, as did Goering, says that vasomotor center always strives to create the most high blood pressure and nerves of Zion ("depressors") and sinocarotidna nerves Goering are in a state of constant struggle with this Trend - the result is something like the famous game "who would attract whom where, and with this game vasomotor center with two pairs known to the reader nerves and creates the blood pressure level, which is not needed at the moment. As a result of such reasoning Goering called the four nerve, we are talking about, Blutdruckzugler - tamers blood pressure.
Employee of Goering Kahn was not quite agree with this view, believing that the sacramental nerves are not tame, not to win, and to regulate the blood pressure. He offered a more modest and, as we now know, the more correct term is "regulators blood pressure" - Blutdruckregler.
Alas, Kahn was unable to finish the begun business, because that was soon destroyed in racist concentration camp.
Carotid sinus interested in many physiologists. This contributed to its topographic location: it is easily available for the preparation, it can be isolated from the General circulation of the animal and modify it not only forces, but also the composition of blood.
In 1927 carotid sinus attracted the attention of the Belgian pharmacist Corneille of Heymans, as well as his father and employees of their laboratory. For six years they studied communication carotid sinus breathing with different chemical irritation and so on. From the walls of the laboratory have published several important volumes on the carotid sinus and especially the carotid body, has linked. "Globus" in translation from Latin - tangle. Carotid Globus is located at the crossroads of the carotid artery. The rabbit he's about the size of a pinhead. Human glomus also very small, weighs only 2 mg.
It turned out that glomus consists mainly of vessels and contains many sensitive nerve endings that respond to the concentration of oxygen and carbon dioxide in the blood (blood). Probably, that is why through glomus passes an inordinate amount of blood: 4-5 times more than in the same size piece of the heart muscle. When glomus tolerate oxygen starvation, respiration increases.
We must say that in 1894, Ivan Petrovich Pavlov theoretically justified the existence of receptors that respond to chemical irritation, but in environment physiologists this almost overlooked. After thirty-two years Belgians father and son Gamasy held principally important study of this problem.
The experiment of Gamanov was set at two dogs. One of them was severed head, remained intact only wandering nerves. The vessels of the head were connected with vessels second dog. Life decapitated body was maintained through artificial respiration. If the vessels of this decapitated body was administered nicotine or stopped CPR, then there is "shortness of breath" isolated head. Subsequently, the same researchers proved that the beginning of a reflex is not only carotid glomus, but arch of the aorta in the field of branching aortic branches of the nerve-depressant, which also has sensitive to chemical irritation tangle. The functions of the aortic and carotid pomozov were identical.
So it was indisputably proved that in the wall of the aorta arch (more precisely, in aortic body, has linked) and in the field of bifurcation of the carotid arteries are highly sensitive receptors that respond to lack of oxygen or too much carbon dioxide in the blood. For these studies Corneille Heymans was awarded the Nobel peace prize.
By the forties of our century, it was found that the aortic and carotid glomus more sensitive to the pressure of oxygen in arterial blood and to various chemicals (such as nicotine and tsitizina)than the nerve centers. Central nervous structures, in contrast, is more sensitive of pomozov to fluctuations in pH and voltage of carbon dioxide. Part of Tabaka, which is used to make life easier quit, is tsitizin, which irritates the same receptors of pomozov that and nicotine.