The immune system is a collection of organs, cells and molecules found throughout the body. Its best known function is to protect us against infections caused by viruses, bacteria, fungi, parasites and others. However, the immune system has many other very important functions for our body. On the one hand, it is responsible for immunosurveillance, i.e. the ability to detect and eliminate cells that have undergone malignant transformation. And if cancer has already occurred, it helps to fight it. It is also responsible for removing waste or toxic products from tissues and, through inflammation, is involved in repairing damaged tissues after illness or trauma. It is also responsible for guarding our body's borders, including the blood-brain barrier, which separates the central nervous system from the rest of our body. At the level of these barriers, and especially the intestinal barrier, it analyses each substance that passes through to decide whether or not it is allowed into the body. It is also involved in the development of all our organs, from the foetal stage to our old age. This is especially important in the brain, where cells of the immune system (resident and migrated), aided by other local cells called glial cells, are largely responsible for neuronal plasticity. This plasticity is the mechanism by which our brain adapts to our environment, the situations we experience, various requirements and the natural development of the body. Thanks to the action of all these cells, the connections between neurons are modified and specialised, and connections or cells that are not useful are eliminated. Finally, it also plays a very important role as a communication system in our body. Because of its ubiquity and its constant interaction with the external environment, and especially with our microbiota, the immune system is able to keep abreast of everything that is going on inside and outside our body. Thus, by manufacturing different substances (pro- and anti-inflammatory cytokines, peptides, amines and others) and releasing them into the extracellular fluid, blood or lymph, it is able to transmit this information to other parts of the body, especially the central nervous system. It is therefore in constant communication with our brain, but also with our endocrine system, and is influenced by hormone levels. Sex hormones, cortisol (stress hormone), thyroid hormones and others are able to regulate the activity of the immune system. This is why all the endocrine disrupting toxins, which we have discussed in other articles, can play a crucial role in the functioning of our body, and in the development of urinary tract infections, which is the subject of this article.
Introduction to endocrine disruptors
The microbiota is also capable of regulating its function. This is why situations of dysbiosis can profoundly alter our health and our defence against infection, as well as all the other functions of this important system. Other mechanisms by which the activity of our immune system can be affected are sleep, emotional or physical stress, physical exercise and diet, especially if there is a deficit of certain vitamins, trace elements or other nutrients such as vitamin C, vitamin D, vitamin E, vitamin B12, zinc, magnesium, selenium, copper, iron, omega-3 fatty acids, etc.
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