The composition and function of the liquor. CSF (cerebrospinal or cerebro with pinalnaya liquid) – a transparent colorless liquid with a low density and a low content of biologically active substances. Liquor contains the same amount of salts as blood plasma. Its pH is close to the pH of the blood, t. e. liquor is a weak alkaline medium. At the same time, there is little protein in the liquor – only 0.12 – 0.33 g / l (65-70 g / l in blood). There are a small number of white blood cells, including lymph and you. However, it lacks enzymes and immunoglobulins.
Liquor performs a variety of physiological functions. From the viewpoint of mechanics liquor is a liquid medium in which n and hoditsya brain. This protects the brain tissue from shocks and concussions. Whether a thief takes part in the diet, the metabolic processes of the nervous maybe, but no, the removal beyond metabolic products. Liquor provide and Vaeth constancy of osmotic aqueous medium, provides normal blood supply in the cranial cavity, and exhibits a protective effect, possessing bactericidal properties and being a component of the immune system of the brain.
Blood circulation of the brain. Brain supply blood to the two carotid and two vertebral arteries, which combine to form at by the arterial circle: the branches of this range are allocated to all regi on our brain. Nerve cells are able to work only in a finless e Boyne delivery of oxygen and glucose, which have reserves of neurons there. Therefore, even a short-term cessation of blood flow to the brain, and leads to a faint, in which consciousness is lost.
The brain consumes much more oxygen than other tissues of the p -organisms. Constituting 2-3 % of the total weight of the body, brain tissue abs on schaet at rest to 13-20 % of the oxygen consumed by the org and closers. This consumption is provided by an intense brainstorm about the current – about 50 ml of blood comes to the brain per minute per 100 g of tissue. The average weight of 1500 g brain continually receives about 750 ml of blood, ie. E. About 13 % of blood volume, which throws left rail e ludochek heart every minute. With intensive mental activity of STI increases overall cerebral blood flow, although only slightly. The brain is like any other organ, requires regular and accurate dosing of the first income and outflow of blood. Of whether brain cells are obtained from the cr to twist the required amount of nutrients in a timely manner whether the beats and lyayutsya products of their life, the health and human life itself. This is because the brain, having a high integral n sivnostyu metabolic processes, a substrate devoid of providing a pit and of nervous tissue by anaerobic (without passing kislor of yes) processes. Therefore, even short-term disruption of the blood supply causes serious changes in the work of the cells. After 1.5 – 2 minutes after the cessation of blood flow, loss of consciousness occurs. If both with krovlivanie extended to 3 minutes, then there are structural Hard Of e Nia nerve cells. In 5-6 minutes irreversible changes occur and their death. Thus, the brain activity is normal in s possible only with sufficient oxygen coming from the blood. Blood flow to the brain is on the trunk with four of the vessels: two internal carotid arteries and two vertebral and p teriyam. These four main arteries, entering the skull, plums and are im e ste and formed on the base of the brain anastomosis ring or blood, which was called the blood (Willis) circle. The design of the circle of Willis ensures the complete possibility of the transfer of blood from the front to the back, from the right half to the left. And due to the exceptionally arterial circle of the brain important for normal Ms of Ned , I just telnosti the body it is called the “heart brain”.
From the circle of Willis originate the vessels that go to the outer surface of the brain, where they form a network of pial vessels, from which the intracerebral arteries, giving numerous brain capillaries, go deep into the brain. Network of pial vessels interconnected multiple anastomoses, which facilitates the rapid movement of blood from Dr. hydrochloric brain area to another, providing, as in the circle of Willis, height of kuyu reliability circulation. A large number of anastomoses between adjacent arteries provides, in addition, the same pressure of blood over the entire surface of the big hemispheres and inside the brain. In general, this structure of the vascular system corresponds to the optimal (cost-effective and efficient) supply of oxygen to the brain tissue.
Capillaries provide delivery to neurons and glia sour on the kind and nutrients and removing carbon dioxide and pour h GOVERNMENTAL metabolites. Thus brain capillaries formed gematoentsef and brain barrier , ie. e. selective permeability for some substances and complete obstruction for other substances. In general, for the brain the Features p at high saturation capillaries, especially in the gray matter, where capillary density is higher than in the white matter, almost 2-3 times. The higher functional activity of a center of the brain than N and conjugate it works, the closer are located and denser braid ner in hydrochloric capillaries cell. Venous brain has a significant track s but higher capacity compared to the arteries. In addition, there are many others on the gochislennye way outflow of blood from the skull. This makes it possible to quickly and evenly output neuron exchange products, creating favorable conditions for the brain to work.