The immune system is an integral part of our body and is responsible for warding off infections. This system works by recognizing cells as dangerous or healthy and responds accordingly. Once it perceives a threat, an immune response is triggered to protect the body. There are three types of immune responses – innate, adaptive, and passive. Innate immunity is overall protection that everyone is born with. For example, skin which prevents germs from coming into the body. Adaptive immunity consists of immune cells that block invaders and help protect the body from diseases. This immunity is obtained over time as new diseases enter the body, antibodies and immune cells remember the material in order to initiate a response that protects against future sicknesses. Measles is an example of this, as once you have had the disease, adaptive immunity stops you from getting it again. The last type is passive immunity which is a short-term immunity you obtain from a person or animal’s antibodies. However, sometimes the immune system does not function properly, as seen in people with allergies or autoimmune diseases. This is because the immune system attacks healthy substances, since it views it as unhealthy, which leads to negative effects. In a healthy immune system, there are DAMP signals which indicate that the cell is dangerous and the system can then mount a response.
There are three types of immune responses – innate, adaptive, and passive.
An important part of the immune system are leukocytes. These are essentially white blood cells and there are two main categories: phagocytes and lymphocytes. Phagocytes attack pathogens and lymphocytes remember past, harmful substances in the body. The white blood cells of the immune system are found in the thymus, spleen, bone marrow, tonsils, appendix, adenoids, and lymph nodes. Once the white blood cells find pathogens they warn other cells and multiply to fight the substance off. All in all, the immune system plays a vital role in keeping the human body healthy.
https://www.medicalnewstoday.com/articles/320101#types-of-white-blood-cell
https://www.hopkinsmedicine.org/health/conditions-and-diseases/the-immune-system
