The circulatory system It is the organ system of the human body that is responsible for moving blood throughout the body to distribute different elements to all its cells. It is made up of two subdivisions: the cardiovascular system, mainly made up of the heart and all blood vessels, and secondly, the lymphatic system, made up of the lymphoid organs and lymphatic vessels..
We can compare the circulatory system with a delivery system, since its components work in unison to transport things from one place to another in the body constantly, delivering some elements and receiving others to take them elsewhere..
The main functions of this system have to do with the transport of gases, nutrients and wastes to and from the cells, as well as with the defense of the body against pathogens, toxins or other potentially dangerous agents..
These functions are not only related to the organs of this system, but also to the main tissue: blood. Blood is made up of cells - red blood cells, white blood cells, and platelets - that are suspended in a fluid known as plasma, rich in different types of soluble molecules and proteins..
It is through the blood and its components that the circulatory system can transport gases (erythrocytes or red blood cells), nutrients (plasma) and cell sentinels for immune protection (leukocytes or white blood cells).
The circulatory system is one of the most important systems in the human body, as its functions are essential for all the processes that take place in each of the cells that make up each of its organs and tissues. Among the most important functions of this system we can mention:
Thanks to the heart, blood is pumped throughout the body to perform one of its fundamental functions: to deliver oxygen and receive carbon dioxide..
On the one hand, the blood is propelled from the heart to the lungs, where it establishes close contact with this portion of the respiratory system, discharging the gases produced by the metabolism of the cells and "recharging" itself with the gases necessary for cellular respiration. On the other hand, the blood is propelled to the rest of the body.
There are two respiratory gases: oxygen, necessary for obtaining energy through respiration, and carbon dioxide (CO₂), the gaseous metabolic waste that is produced during respiration and that must be eliminated from cells and from the body. body through the lungs.
Concave, disc-shaped cells called erythrocytes or red blood cells are responsible for transporting these gases in the blood. Inside these cells have a protein, the hemoglobin, which is able to bind to the two gases: oxygen in the lungs, to deliver it to the cells, and CO₂ in the cells, to deliver it to the lungs.
While the digestive system is responsible for physically and chemically "breaking" the particles of the food that we consume every day to extract the energy that our body needs to survive, the circulatory system is responsible for the transport of the molecules that are absorbed.
This is possible because the intestinal absorption phase occurs in such a way that the nutrients reach the blood and lymph, from where they are distributed and distributed to all body cells by the circulatory system..
Carbon dioxide is not the only metabolic waste that is produced by cells, other compounds such as urea, certain ions and molecules that are not necessary for the body, as well as excess fluid, must be eliminated and are transported by the blood.
The cells discharge these wastes to the blood tissue and this blood is transported, driven by the pumping of the heart, to the kidneys -which are part of the excretory system- where they are eliminated in the form of urine..
The circulatory system also participates in the regulation of two very important aspects:
- Body temperature, thanks to the movement of blood from the surface of the skin to the innermost regions and vice versa - depending on the ambient temperature.
- Hormonal regulation, due to the transport of hormones from their production site to distant organs or target tissues.
The circulatory system is essential for the protection of our body against dangerous microorganisms or toxic substances, as well as to prevent excessive blood loss due to injuries. These functions have to do with:
- The immune functions of the cells that circulate in the blood, the leukocytes or white blood cells, that travel in the blood and that mature in the lymphoid organs.
- The coagulation mechanisms that act on blood vessels that have suffered some physical damage and that prevent blood loss.
The circulatory system is made up of two major subdivisions: the cardiovascular system and the lymphatic system..
The former is made up of the heart and blood vessels, while the latter is made up of the lymphatic vessels and lymphoid tissues within the spleen, thymus, tonsils, and lymph nodes..
The heart is the muscular pump that moves all the blood throughout the body. The human body is generally the size of a fist and is located in the middle-left region of the chest, between both lungs..
This organ is made up of four hollow chambers made up of muscle: the atria and ventricles, left and right. The atria are the upper chambers and the ventricles the lower chambers.
The left atrium is connected to the left ventricle and the right atrium to the right ventricle, but the left atrium and left ventricle are not directly connected to the right atrium and ventricle, they are indirectly associated through the pulmonary circulation.
Between these chambers, in addition, there is a series of valves that prevent the movement of blood in the opposite direction, so they are essential for the proper functioning of the heart.
The atria and ventricles have the ability to contract rhythmically to propel blood into the blood vessels and from there throughout the body.
The right atrium receives blood from the tissues, which is poor in oxygen, and from there conducts it to the right ventricle, from where it is pumped into the lungs. The left atrium receives oxygenated blood from the lungs and carries it to the left ventricle, which pumps it to the rest of the body..
The muscular walls of the atria and ventricles contract to expel blood within them and eventually direct it to its final destination. The heart contracts continuously, our life depends on it; it does when we eat, read, walk, talk, exercise, and even when we sleep.
It is important to mention that, although the heart is also connected to the nervous system, which is what drives the contraction of other muscles in our body, its contraction (which causes blood to pump) does not depend on it, but on the cells themselves of the heart, which are spontaneously excited.
Blood vessels function as the tubing the heart uses to distribute blood to the tissues and to carry it back to itself. There are different types of blood vessels:
- The arteries They are those that are directly connected to the heart and the ventricles, that is, they are responsible for transporting blood out of the heart. The arteries branch progressively, forming smaller and smaller "branches"; the smallest are known as arterioles.
- The veins, Instead, they are responsible for transporting blood back to the heart. These also branch out, and the smallest of all are called venules.
- The capillaries, they are the smallest blood vessels of all; all the exchange of gases, fluids, nutrients and wastes that is related to the transport functions of the circulatory system occurs through these numerous and tiny blood vessels.
The lymphatic system is a network of organs and tissues whose main function is to transport a fluid known as lymph, composed, among many things, of a small part of the fluid fraction of the blood (plasma) that leaves the capillaries..
Lymph carries cells, fats and other substances, and is eventually returned to the blood tissue, but first it is "cleaned" in structures known as lymph nodes, which are distributed throughout the body..
In addition to its transport and filtering functions, the lymphatic system plays a crucial role for the immune system, which is the body's main defense system..
The cells of this system, the lymphocytes, are specialized in the recognition and elimination of foreign agents that enter our body and that can be harmful..
Like the cardiovascular system, the lymphatic system uses a network of pipes for distribution throughout the body, but its components are known as lymphatic vessels. The largest lymphatic vessels are called ducts and the smallest are lymphatic capillaries..
Some cells of the lymphatic system are produced by germinal centers in the lymphoid organs: the thymus, tonsils, and spleen; while others are produced by the bone marrow, just like red blood cells. Given the important task of these cells, these organs are also very important for the health of our body.
The circulatory system works thanks to the heart, which keeps the blood moving in a closed circuit, which begins and ends in the heart itself.
The right side of the heart is responsible for pushing the blood to the lungs, where it can be charged with oxygen and release the waste CO₂ that it brought from the rest of the body..
The left side, on the other hand, collects the oxygenated blood and sends it to the rest of the body to deliver oxygen and nutrients to the cells..
Each contraction of the heart causes the movement of the blood to be constant, so it is pushed back towards the heart, where the process is repeated..
Blood that derives from the left chambers of the heart is known as systemic blood, while blood that derives from the right chambers is known as pulmonary blood. Both constitute, anatomically speaking, the systemic and pulmonary circulation..
Like any system in our body, the circulatory system can suffer damage and / or diseases, some of which we can prevent just by taking into consideration some tips:
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