What is the placental barrier?

Today the term "placenta" does not surprise anyone. Modern girls are aware of pregnancy and childbirth much better than their grandmothers and mothers. However, for the most part, this knowledge is superficial. So today we want to talk about what the placental barrier is in the womb of the mother. At first glance, what is incomprehensible? The baby's place has the properties to protect the developing embryo from harmful effects and toxic substances. In fact, this body is a real mystery and a miracle of nature.

Under protection

The placental barrier is a kind of immune system. It serves as a boundary between two organisms. It is the placenta that ensures their normal coexistence and the absence of an immunological conflict. The first trimester of pregnancy is the most difficult. Partly because the placenta is not yet formed, it means that the embryo's body is completely unprotected. Approximately from 12 weeks it is fully included in the work. From now on, she is ready to perform all her functions.

How is the placenta?

This is an important point, without which we can not continue our conversation. The very word "placenta" came to us from Latin. It is translated as "flat cake". The main part of it are special villi, which begin to form from the first days of pregnancy. Every day they are more and more branched. At the same time, the blood of the child is inside them. At the same time, maternal blood enriched with nutrients comes from outside. That is, the placental barrier carries in itself primarily a separation function. This is very important, since this body regulates the metabolism between two closed systems. According to this statement, the external and internal sides of the placenta have a different structure. Inside, it is smooth. The outer side is uneven, lobed.

Barrier function

What does the term "placental barrier" include? Let's go a little further in the direction of the physiology of the ongoing processes. As already mentioned, it is the unique villi that provide the substance exchange between the woman and the embryo. Maternal blood brings the baby oxygen and nutrients, and the fetus gives the pregnant girl carbon dioxide. Excretory system while they have one for two. And herein lies the greatest mystery. The placental barrier divides the blood of the mother and fetus so well that they do not mix.

At first glance it seems unimaginable, but the two vascular systems are separated by a unique membrane septum. She selectively misses what is important for the development of the fetus. On the other hand, toxic, harmful and dangerous substances are delayed here. Therefore, doctors say that starting from the 12th week the future mother can relax a little. The placenta is able to protect the child from many unfavorable factors.

Only the most important

Through the placental barrier, all the necessary nutrients pass through, as well as oxygen. If the doctor observes the pathology of developing the fetus, he can prescribe special drugs that enhance the blood supply of the placenta. So, increase the amount of oxygen that comes to the baby. However, not all so simple. Membrane septum delays the bacteria and viruses contained in the mother's blood, as well as antibodies that are produced in the Rh rhesus-conflict. That is, the unique structure of this membrane is tuned to preserve the fetus in a variety of situations.

It should be noted that the septum is highly selective. Across the placental barrier, the same substances differently overcome this line in the direction of the mother and fetus. For example, fluorine very easily and quickly penetrates from woman to baby, but does not go back at all. A similar situation with bromine.

Due to what is the regulation of metabolism?

We have already told the reader that the placental barrier separates the lymph of the mother and fetus. How did nature manage to launch such a perfect regulation mechanism, when what is needed is penetrating the barrier, and what is harmful is delayed? In fact, we are talking about two mechanisms at once. Next, a little more detail on each of them.

First of all, we are interested in how the supply of vital, nutritious elements is regulated. Here everything is quite simple. Lipids and carbohydrates, proteins and vitamins are constantly present in the mother's blood. Hence, the body can work out a balanced scheme. It will initially imply that the concentration of certain substances in the blood of the mother and the child is different.

Permeability of the placenta

Much more difficult when we talk about toxic substances that enter the body of a pregnant woman. The placental barrier separates lymph and blood. Hence, those toxins that have passed through the bloodstream of the mother will not fall into the pure state to the fetus. However, after passing through the natural filters (liver and kidneys) in a residual form, they can still hurt the baby. The fact is that accidentally ingested substances (chemicals, preparations) in the mother's body are much more difficult to stop. They often have the property of overcoming the placental barrier.

Limited barrier functions

Nature could not envisage the development of modern industry. Therefore, products of chemical production relatively easily pass the natural barrier. They pose a threat to the growth and development of the fetus. The degree of penetration through the placenta depends on the properties and characteristics of the particular substance. We note only a few points, in fact, there are many more. Thus, medicinal substances with a molecular weight (less than 600 g / mol) go through the placental barrier much faster. At the same time, those that have a smaller indicator hardly penetrate. For example, it is insulin and heparin, which can be prescribed without fear during pregnancy.

There is one more sign. Fat-soluble substances penetrate the placenta much better than water-soluble substances. Therefore, hydrophilic compounds are more desirable. In addition, doctors know that the probability of penetration of the substance through the placenta depends on the time the drug is in the blood. All long-acting drugs are more dangerous than those that are quickly metabolized.