The immune system is an invisible barrier that protects our body and allows us to not get sick by holding high the natural defenses of the organism. Without him we could not live for a long time: we don’t realize it but every day in our body plays a daily struggle for survival. To ensure the immune system has a control network, a sort of “intelligence”, that the square, squadrons and artillery throughout the body, ready to launch attacks against viruses, bacteria, and pathogens of every kind.
But exactly what is the immune system? Where is it located? What and how does it work?
What is the immune system?
The immune system is composed of a number of important mechanisms that defend our body from the onslaught of “invaders from outside” that might compromise our health. The invaders are viruses, bacteria or other harmful substances that could harm us in a permanent way.
We do not realize it, but every day we are subjected to this type of “assaults”. When the defense systems, i.e. the immune system, they react quickly, before the pathogens can be the crack, our body does not feel anything.
However, when the attack is massive, and our immune system does not immediately recognize the pathogen enemy, we experience a series of symptoms which indicate that your body is fighting the infection. The fever caused by the influenza virus is the example par excellence.
the immune system: viruses and bacteria
Viruses and bacteria: what’s the difference?
Bacteria are tiny single-cell organisms that are able to reproduce themselves and survive in different environments, withstanding the heat and the extreme cold. Almost all bacteria are harmless and some help even to fight cancer cells and support the digestion and the destruction of microbes.
Viruses, unlike bacteria, cannot survive without a receiver. Can only reproduce by attaching itself to the cells. In most cases, programming the cells to “stick” to the production of other viruses. In other cases, are responsible for the transformation of normal cells into malignant or cancerous.
Many diseases can be bacterial than viral in nature. So it happens for meningitis, diarrhea, and pneumonia. To understand the origin of these and other pathologies is necessary to make some analysis, such as:
analysis of the urine
blood tests to confirm the diagnosis
the “pad” of tissue to identify bacteria and viruses.
sometimes a tissue biopsy may be necessary.
We can conclude that for distinguishing a viral infection from a bacterial do not need to look, neither the causes nor symptoms. The best thing to do is consult the doctor, because only with a specific analysis of it will be possible to distinguish them and prescribe the best treatment.
Resistance to antibiotics
The treatment of the infection bacterial is treated with antibiotics.
Unfortunately, the bacteria can easily adapt and the excessive use of antibiotics increases resistance, making them ineffective.
The development and use of antibiotics, starting from the second half of the TWENTIETH century, has revolutionized the approach to treatment and prevention of infectious diseases and of the infections considered in the past were incurable. However
the emergence of resistance to antibiotics is currently the most fast development of new molecules.
In addition, the emergence of pathogens resistant to multiple antibiotics further reduces the possibility of effective treatment. It is to be noted that this phenomenon often affects the infections related to health care, that arise and spread within hospitals and other healthcare facilities.
The problem of antibiotic resistance is complex, since it is based on a variety of factors:
the increased use of these drugs (including the use is not appropriate, such as the use of antibiotics to treat the flu). This
increases the selective pressure favouring the emergence, multiplication and spread of resistant strains.
the spread of hospital infections by micro-organisms to antibiotic-resistant.
an increase in international travel and therefore a greater diffusion of the strains.
where is the immune system
Where is the immune system?
The ability of the body to respond to the attacks of viruses, bacteria and other harmful substances is called immune response. But what are the organs that respond to the “assaults” of a pathogen?
The immune system consists of specialized cells called immune cells. The leukocytes (or white cells) present in the blood make up a large part of the immune system. Considering that the blood circulates through our entire body, it is easy to understand as well as leukocytes are present all over the world.
Thus, we can say that the immune system can be found everywhere and in every place in our body. There are also a number of bodies where the white cells are present in massive quantities as the spleen, lymph nodes, tonsils, the thymus, and tissues that communicate via the lymphatic vessels.
If the pathogens attack the lungs, skin and intestines, came to the rescue of the macrophage: a type of white blood cells present in these organs.
When we get a wound, the germs can enter our body through the cut. If this happens, neutrophils, a group of white blood cells, move towards the area damaged, to destroy the germs.
The immune response
The immune response is of two types:
Immune response innate (or nonspecific), which is a defense mechanism, general, present from birth, which acts quickly (minutes or hours) and indiscriminately against any external agent. Said in more technical terms, cells have the ability to recognize “self” from “not self”, that is the one that is part of the organisation in relation to what it isn’t. And attacks him.
The adaptive immune response (specific or or adoptive). This develops slowly after the first encounter with a specific pathogen (in the span of a few days), but it retains some memory to act more quickly in response to further exposures in the future.
the immune system self-regulates
The immune system self-regulates
The immune response should be triggered only when it is necessary. The fever is caused by the immune response: but what would happen if the temperature would not drop after the virus has been fought and eliminated?
The immune system has several strategies to stop an immune reaction exaggerated.
Has molecules and cells that have the task to turn off the immune response. A cell that specializes in this task is the lymphocyte, T regulatory.
The immune memory
Each winter, there always comes a new influenza virus, and in a few weeks millions of people fall victim to influenza. If we have to deal with a healthy physique, in a few days, thanks to the fever, our immune system defeats the virus. If then, within the space of a few months, you should encounter the same viral strain, many do not ammalerebbero even, or would have milder symptoms.
This happens because, as we have seen, ammalandosi the first time, and defeating the virus, the people who have been a victim of that virus have acquired an immunity specific to that particular pathogen.
This skill is another important function of the immune system: it is able to remember pathogens that have infected, even decades. This ability is called immunological memory and is the basis of vaccines.
After the vaccination, our body “remembers” in a specific manner, these viruses or bacteria. Therefore, in the case in which you come in contact with the virus or the bacterium in the environment, the antibodies produced following the vaccination, quickly recognize and destroy the organism before it has the chance to make you ill.
The vaccines that we are inoculated to contain pathogens that have been weakened so that the body can immunize itself against them without getting sick.
Vaccinations to which we are subject increase the number of germs that our body can recognize.
Vaccinations have drastically reduced the cases of diseases caused by viruses, like polio, chicken pox and measles, and other diseases such as influenza, hepatitis A, hepatitis B, and human papilloma virus.
What is an allergy?
Also allergies are immune reactions. Pollen, dust mites, and sometimes the same food can cause allergies and are called allergens. When the immune system fights against substances that are not generally dangerous, it has an allergy. Most of the allergies is caused by a group of cells of the immune system called mast cells.