How does the immune system work?

The immune system is one of the “smartest” systems in the human body. It has the ability to remember and learn, quickly assess external stimuli in terms of their potential harmfulness to the body and select the appropriate response to the threat. The immune system is made up of many parts and organs that perform specific functions. Read more: Once upon a time there was a war author of the photo BE&W

Bone marrow – the soft tissue inside long bones, is the place where blood cells are formed, e.g. lymphocytes. T lymphocytes play a regulatory role, B lymphocytes are responsible for the so-called humoral immune response and antibody production. author of the photo BE&W

Thymus – the central organ of the immune system, located in the chest. It plays a role in shaping specific, ie acquired, immunity, is responsible for the number and education of T lymphocytes. The thymus increases in size in young children and then disappears in adults. author of the photo BE&W

Spleen –

Lymph nodes play an important role in trying to prevent the spread of infection or the cancer process. The photo shows the lymphatic system in the area of ​​the arm. Lymphatic vessels are marked in green, lymph nodes are marked in blue. author of the photo BE&W

T lymphocytes – cells of the immune system, are born in the bone marrow and travel to the thymus, and then to the lymphatic organs and peripheral blood. There are many types of T lymphocytes: cytotoxic T lymphocytes destroy other cells, helper T lymphocytes support the work of B lymphocytes, suppressive T lymphocytes act as mediators. author of the photo BE&W

B lymphocytes are formed in the bone marrow, they are responsible for the so-called a humoral immune response in which the antibodies they produce are of key importance. One type of antibody can neutralize one type of enemy. Mature B lymphocytes are able to release up to 2. antibodies per second. The figure shows the pattern of antibody production (yellow) by B lymphocytes (purple) under the influence of T lymphocytes (blue) recognizing specific bacteria (green). author of the photo BE&W

The bacteria in the gut can interfere with the local immune system. The photo shows bacteria of the genus Lactobacillus (yellow) – components of the normal flora of the digestive system – attached to the surface of the intestinal villi (red). author of the photo BE&W

Diseases of the immune system consisting in the hypersensitivity of the system lead to the development of allergies (e.g. hay fever), in the course of which the immune response is disproportionate to the degree of risk. The figure shows a pattern of an allergic reaction of the nasal mucosa, where allergen is recognized (gray) and mucus secretion (orange) is increased by epithelial cells (red). author of the photo BE&W

One of the diseases in which there is an immune response against its own tissues (the so-called autoimmune disease) is Crohn’s disease, where inflammation and ulceration occur in various parts of the digestive system. The photo shows the intestine of the sick person. Read more about the functioning of the immune system in the article Once upon a war photo author BE&W

In autoimmune diseases such as multiple sclerosis MS, the immune system starts attacking its own antigens, destroying the body’s tissues. The figure shows the process of destroying the myelin sheath of nerves (purple) by cells of the immune system (blue), which leads to damage to the nervous system and the development of MS. author of the photo BE&W

Individual components of the immune system may also undergo uncontrolled neoplastic processes. An example of a cancer of part of the immune system is hairy cell leukemia. The picture shows lymphocytes with a characteristic “hairy” surface made of folds of the cell membrane. author of the photo BE&W

The immune system has a protective function, counteracting neoplastic disease – it prevents the formation of a tumor. Lymphocytes recognize and destroy cancer cells. The photo shows a large cancer cell (brown) attacked by two lymphocytes (green). author of the photo BE&W