- WHAT IS THE HEART?
Our heart, which contains many miraculous mechanisms from its micro structure to its macro structure, is, in its simplest terms, a "pump" or " It is a suction-discharge pump system. This pump system ensures that the "blood" required to transport all the substances required for the continuation of life to the remotest corners of the body circulates continuously and without interruption. However, in simple suction-discharge pump systems, the flow of water is intermittent rather than continuous, while blood flows uninterruptedly forward in the body. In other words, even when the heart relaxes and receives blood, the blood continues to flow forward without hesitation.
The work done by the heart is briefly seen in the diagram below. If we talk about it in one sentence: The heart takes back the clean blood it sends to the body after it is used, sends it to the lungs for cleaning, and then takes it back after it is cleaned and sends it to the body.
- WHAT IS IT COMPOSED OF?
The heart is our most vital organ, located at the center of the circulatory system. It is located just behind the anterior chest wall, slightly to the left, in the middle of both lungs, in the front part of the esophagus.
In order to understand heart diseases, it is first necessary to understand the structure of the heart and what it consists of. Since the details will be discussed in the topic of diseases, let's list the building blocks of the heart as main headings.
1. MUSCLES (MYOCHARD)
What the heart ultimately does is "pump blood". Accordingly, the basis of the system will of course be muscles. Heart muscle is included in the smooth muscle class that "works involuntarily (beyond our will)".
2.ELECTRIC (Rhythm and Conduction) SYSTEM
Yes, we said that heart muscles have a special structure that works beyond our will. So what is the mechanism that activates these muscles? Here it would be appropriate to make the following sentence: “The heart produces and uses its own electricity. The muscles are driven to contract with this electricity.
3. VESSELS
While the muscles contract with the help of the electrical system, they receive blood to provide the necessary energy. It also brings veins. This system called "Coronary Vessels" is responsible for diseases of the heart. It occupies an important place in the Because heart attacks, which are among the leading causes of death, occur due to blockage of this vascular system.
4. VALVES
When blood fills the heart, the valves that provide passage between the cavities direct the blood movement by opening and closing synchronously, preventing the blood from flowing in the opposite direction due to the pressures inside the heart.
5. HEART MEMBRANES (PERICARDY)
The membrane system surrounding the heart, which is in constant motion within the chest cavity, both protects the heart and contains the small amount of fluid it contains. It prevents friction.
6.MAJOR VESSELS
When the heart pumps, the blood first opens the Aortic valve with the pressure generated and moves into the Aorta, the main artery of the body. Three veins are separated from the area where the aorta curves, and blood is delivered to the arms, upper chest area, neck and all structures in the head. After the aortic arch, the part called the Descending Aorta begins and the blood movement that continues from here reaches all the remaining body parts.
Used by the body, it has released its oxygen to the tissues, so "oxygen-poor blood" ("dirty blood", although it is a wrong expression) is transferred from the Lower and Upper Vena Cava to the Right Atrium of the heart (Right) through the venous networks. Enters) the atrium. From here, it is first passed through the Tricuspid valve to the Right Ventricle (Right Ventricle), then again by the pumping of the heart, it passes through the Pulmonary valve and is transmitted into the Main Pulmonary Vein. The Main Pulmonary Artery is divided into two branches, right and left, and blood is delivered to both lung regions.
In the extensive vascular network of the lung, blood meets the oxygen taken from the air and becomes "oxygen-rich" (clean!). ) becomes. Oxygenated blood reaches the Left Atrium (Left Atrium) via two Pulmonary Veins coming from the right and left Lungs, and from there it passes through the Mitral Valve and reaches the Left Ventricle. As we mentioned, the left ventricle is the main heart chamber that pumps blood to the body.
AND HOW DOES IT WORK?
Again To put it briefly;
In the Sinoatrial (SA) node, which is located in the right atrium and is under the control of the brain and hormones, and which we can call the "electrical generator", the electric current generated by the displacement of electrically charged ions in and out of the cell, ensures the functioning of the heart. Electric current first spreads to the atria, causing the atria to contract and discharge the blood inside them into the ventricles through the Tricuspid valve on the right side and the Mitral valve on the left side.
Meanwhile, the electric current transmitted from the SA node to the AV node (a kind of electrical transfer transformer) is kept there for a very short time. Because the atria have not finished contracting and discharging the blood into the ventricles yet. If the electric current had not been kept here, the ventricles would have started to contract before the atria had fully emptied their contents, and the blood flow order would have been disrupted.
Yes, after a short wait in the AV node, the electricity transmitted downwards spread rapidly to both ventricles through the right and left branches of the conduction system, causes the ventricles to contract. The ventricles contract, open the Aortic and Pulmonary valves with pressure and send the blood inside them. The right side goes to the lungs via the Pulmonary artery, and the left side goes to the whole body via the Aorta... After the pumping process is completed in a short time, the electrical movement on the conduction system returns to its resting position with the movement of ions inside and outside the cells, and the ventricular muscles of the heart begin to relax. . As the ventricles return to their resting position, the SA node is about to contract the atria again by producing a new electrical current. As the ventricles relax, they absorb the blood inside the atria with the help of the contraction of the atria... The ventricles fill and the cycle continues in this way throughout life, as it started in the 7th week in the womb. The energy required for all these processes is provided to the heart by the coronary vessels.
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