BXBX NOVEL Chapter 2580: 【2580】Defective wall
Besides, there are very few heart diseases that can be diagnosed solely by ECG and chest X-ray.
For the simplest example, a sixteen-year-old girl in bed number 12 suffered from atrial septal defect.
This disease can be regarded as a big or small disease. Interestingly, it is a congenital disease, which means that it is born with an abnormality from embryonic development. The next odd thing is that many cases of this congenital disease were diagnosed in adults, and it turned into a heart malformation disease that is common in adults. Explain what? It shows that it is difficult to find it, and it cannot be done without accurate medical detection equipment. To be precise, a heart ultrasound needs to be done.
Why can’t we detect this disease in time with electrocardiogram and chest X-ray? Let’s talk about its pathogenesis.
The atrial septum is similar to a wall, and it is known from the name that it is located between the left atrium and the right atrium. The job of the wall is to block, the atrial septum blocks the blood of the left atrium and the blood of the right atrium, so that the blood of these two atria cannot communicate.
The name atrial septal defect is more vivid, describing the characteristics of the disease: the wall is missing. Defective wall shows, either a hole, one, two or three, or it is directly missing, and the whole wall is missing a piece for you.
Since the cause of this disease is congenital, we must start with how the atrial septum grows.
In the process of building the wall of the room partition, you need to build an initial wall first, which is called the primary partition. If there is an abnormal missing block in the process of the primary partition, the space left is called the primary hole. The primary hole has been unable to fill, called the primary hole atrial septal defect. This is one of the types of atrial septal defect.
According to the above statement, the primary diaphragm needs to be completely built, so that the disease will not occur. The problem is that the process of building the walls of the inter-room is the baby's fetus in the mother's womb.
There is a big problem with building walls during the fetal period: the oxygen and other nutrients that the baby absorbs during the fetal period is obtained through the placenta, not through the pulmonary circulation of their own breathing. Therefore, the right atrium and left atrium of the fetus need to be connected, so that the blood rich in blood oxygen and other nutrients in the placenta can directly flow into the left atrium and left ventricle of the baby, and then go to the whole systemic circulation to nourish the whole body.
Having said that, building a wall between rooms cannot block the entire wall, what should I do?
Had to degenerate a hole in the original wall that was built. This hole grew out later, so it was called a secondary hole.
Secondary holes are useful to the baby during the fetal period, but they are useless after the child is born, and if they remain there, problems will arise. The human body is prepared to block the hole in advance, so another wall grows on the original wall called the secondary diaphragm. This secondary diaphragm is equivalent to a patch for plugging the hole. At this time, the secondary foramen has another name, which many mothers have heard: the famous foramen ovale.
To sum up, in order to keep the left atrium and the right atrium connected during the fetal period, the secondary diaphragm and the primary diaphragm are not fused. This allows blood to enter the foramen ovale of the right atrium, and then pass through the gap between the primary and secondary diaphragms to the left atrium.
(end of this chapter)