What is gas exchange? Virtually no living creature can do without it. Gas exchange in the lungs and tissues, as well as blood, helps to saturate cells with nutrients. Thanks to him, we get energy and vitality.
What is gas exchange?
Living organisms need air to exist. It is a mixture of many gases, the bulk of which are oxygen and nitrogen. Both of these gases are essential components to ensure the normal functioning of organisms.
In the course of evolution, different species developed their adaptations for their production, some developed lungs, others developed gills, and still others used only integuments. With the help of these organs gas exchange is carried out.
What is gas exchange? This is a process of interaction between the external environment and living cells, during which the exchange of oxygen and carbon dioxide occurs. During breathing, oxygen enters the body along with air. Saturating all cells and tissues, it participates in the oxidative reaction, turning into carbon dioxide, which is excreted from the body along with other metabolic products.
Gas exchange in the lungs
Every day we breathe in more than 12 kilograms of air. The lungs help us with this. They are the most voluminous organ, capable of holding up to 3 liters of air in one full deep breath. Gas exchange in the lungs occurs with the help of alveoli - numerous vesicles that are intertwined with blood vessels.
Air enters them through the upper respiratory tract, passing through the trachea and bronchi. Capillaries connected with the alveoli take air and carry it through the circulatory system. At the same time, they give the alveoli carbon dioxide, which leaves the body along with exhalation.
The exchange process between the alveoli and blood vessels is called bilateral diffusion. It occurs in just a few seconds and is carried out thanks to the difference in pressure. In atmospheric air saturated with oxygen, it is larger, so it rushes to the capillaries. Carbon dioxide has less pressure, which is why it is pushed into the alveoli.
Circulation
Without a circulatory system, gas exchange in the lungs and tissues would not have been possible. Our body is penetrated by many blood vessels of various lengths and diameters. They are represented by arteries, veins, capillaries, venules, etc. In the blood vessels continuously circulate, promoting the exchange of gases and substances.
Gas exchange in the blood is carried out using two circles of blood circulation. When breathing, air begins to move in a large circle. In the blood, it is transported by attaching itself to a special hemoglobin protein, which is found in red blood cells.
From the alveoli, air enters the capillaries, and then into the arteries, heading straight to the heart. In our body, it plays the role of a powerful pump, pumping oxygenated blood to tissues and cells. They, in turn, donate blood filled with carbon dioxide, directing it through the venules and veins back to the heart.
Passing through the right atrium, venous blood completes the great circle. In the right ventricle begins a small circle of blood circulation. On it, blood is distilled into the pulmonary trunk. It moves through the arteries, arterioles and capillaries, where it exchanges air with the alveoli to start the cycle anew.
Tissue exchange
So, we know what gas exchange of the lungs and blood is. Both systems transfer gases and exchange them. But tissue plays a key role. They are the main processes that change the chemical composition of air.
Arterial blood saturates the cells with oxygen, which triggers a number of redox reactions in them. In biology, they are called the Krebs cycle. For their implementation, enzymes are needed, which also come with blood.
During the Krebs cycle , citric, acetic and other acids are formed, products for the oxidation of fats, amino acids and glucose. This is one of the most important stages that accompanies gas exchange in tissues. During its course, the energy necessary for the operation of all organs and systems of the body is released.
To carry out the reaction, oxygen is actively used. Gradually, it oxidizes, turning into carbon dioxide - CO 2 , which is released from cells and tissues into the blood, then into the lungs and atmosphere.
Gas exchange in animals
The structure of the body and organ systems in many animals varies significantly. The most similar to humans are mammals. Small animals, such as planaria, do not have complex metabolic systems. For breathing, they use external covers.
Amphibians use the skin, as well as the mouth and lungs for breathing. In most animals living in water, gas exchange is carried out using gills. They are thin plates connected to capillaries and transporting oxygen from water in them.
Arthropods, such as millipedes, wood lice, spiders, insects, do not have lungs. Over the entire surface of the body, they have tracheas that direct air directly to the cells. Such a system allows them to move quickly without experiencing shortness of breath and fatigue, because the process of energy formation is faster.
Gas exchange in plants
Unlike animals, in plants, gas exchange in tissues includes the consumption of both oxygen and carbon dioxide. They consume oxygen in the process of respiration. Plants do not have special organs for this, so air enters them through all parts of the body.
As a rule, the leaves have the largest area, and most of the air falls on them. Oxygen enters them through small openings between the cells, called stomata, and is processed and excreted as carbon dioxide, as in animals.
A distinctive feature of plants is the ability to photosynthesis. So, they can convert inorganic components into organic ones with the help of light and enzymes. During photosynthesis, carbon dioxide is absorbed and oxygen is produced, so plants are real “factories” for air enrichment.
Features
Gas exchange is one of the most important functions of any living organism. It is carried out with the help of breathing and blood circulation, contributing to the release of energy and metabolism. The features of gas exchange are that it does not always proceed the same way.
First of all, it is impossible without breathing; stopping it for 4 minutes can lead to impaired functioning of brain cells. As a result, the body dies. There are many diseases in which there is a violation of gas exchange. Tissues do not receive enough oxygen, which slows down their development and function.
Uneven gas exchange is observed in healthy people. It increases significantly with increased muscle work. In just six minutes, he reaches maximum power and adheres to it. However, when the load increases, the amount of oxygen can begin to increase, which also unpleasantly affects the well-being of the body.