The human body is exposed to many diseases: viral, bacterial, fungal or mixed. To protect the body, nature has created various barriers, because without them, foreign microorganisms would easily enter our body. But what is a barrier?
Natural barrier of the body
By the classical definition, a barrier is any structure that prevents penetration. For example, the skin is also a barrier, and it has a protective function, at least from physical influence on it.
All of the above types of microorganisms can also enter the brain, causing serious infectious diseases such as cerebral syphilis, meningitis, encephalitis, and so on, and it is quite difficult to cure these infections. And an interesting question arises why the infection from the bloodstream got into the brain, but the injected drugs did not. The answer is simple: all patterns lie in the brain barrier, or more precisely, in the blood-brain barrier.
Blood-brain barrier: what is it?
The blood-brain barrier is a barrier betweencapillary blood and brain cells, which protects it from the penetration of foreign substances / microorganisms that can cause damage.
It also performs the function of independent regulation of the composition of the nutrient medium in which the brain cells live. Of course, this barrier does not protect the brain 100%. It depends on the duration of stay of the substance in the blood, its concentration; external influences; body condition and so on.
What is the blood-brain barrier made of?
This is not an organ like the kidney, stomach or spleen. It cannot be seen on ultrasound or felt through the anterior abdominal wall. The brain barrier is a collection of anatomical functions.
What it consists of:
- Cerebral capillaries. The walls of the capillary have neither windows nor doors. Certain cells are layered on top of each other, and the junctions are covered with special plates. The spaces between the cells are quite small, so the movement of fluid from the capillary vessel into the tissue goes through its wall.
- The capillary wall alone is indispensable here. The second defense is located between the capillary and the brain cell. In this gap there is a layer of neuroglia, consisting of a plexus of stellate cells of astrocytes and their processes of dendrites. Neuroglia change the oxidative potential of incoming elements, which determines the permeability of the brain barrier.
- The soft membranes of the brain and the vessels of the lateral ventricles also take part in protecting the brain. Permeabilitybrain vessels are lower than capillaries, and the gaps between cells in the capillary wall are wider. This is where the third stage of protection takes place.
In general, we found out what a barrier is, why it is needed and what it consists of.
