What protects the horse’s brain from overheating
It is known that at a temperature of about +40.5 * C the brain perishes.
But at the same time the body temperature of the horse during the race reaches 45-46 * C.
How so? Animals capable of rapid movement usually have an extensive network of arteries that cools the blood warmed by the load before it enters the brain. However, the horse does not have such a device. What protects the horse’s brain?
Pharyngeal bags filled with air, were discovered by scientists in horses a few centuries ago. Since then, their appointment has been controversial. Someone thought that the bags were needed to hold the horse’s head on the surface of the water while it was swimming.
Another version is that the bags are necessary for making sounds by a horse. But, firstly, a rare horse will voluntarily swim into the water to swim, and secondly, when in the XIX century some researcher filled the bags with gypsum, the unfortunate animal did not become dumb. Recently an employee of the Danish Vet. In the lab, Kit Baptist suggested that it was the pharyngeal pouches that protect the brain from overheating during physical exertion. When the blood of the artery carrying it to the brain reaches the sacs filled with air, it is cooled.
An experiment was conducted in the laboratory: pumping air into the sacs, saline was driven out through the arteries of dead horses. The fluid entered the brain chilled, but the experiment was considered invalid: it was required to spend it with live horses.
Then the vets placed temperature probes in the carotid arteries of four experimental animals. While the horses were moving slowly, the temperature of the blood and air in the sacs corresponded to normal body temperature. After a few minutes of gallop, the blood was heated, and when passing through the air sacs, it cooled down, while the air temperature in the sacs remained invariably low. So confirmed version of Baptista.