Have you ever wondered why you get sick? Or how your body recovers from different illnesses? This is all thanks to your immune system! The immune system is a large network of cells, organs, and tissues that are responsible for protecting us against tiny invaders-- also called pathogens--such as bacteria, viruses, and parasites.

In order to fight the foreign invaders that make us sick, the organs, tissues, and cells in the immune system must work together to keep us healthy. The main parts of the immune system are white blood cells, antibodies, the spleen, the bone marrow, the lymph nodes, and the thymus. The immune system establishes many different kinds of cells that all destroy disease-causing germs. Some of these cells are uniquely designed to fight off a specific disease and wait in the immune system to attack the potential invaders.

The white blood cells are an essential part of our immune system. They are made in the bone marrow as well as the thymus and move throughout the body looking to detect any foreign invaders. There are many different types of white blood cells, all of which have different functions. These can ranging from memory cells—which can remember the germs that have already attacked the body and help fight off new attacks by a specific antigen—to T cells—which help get rid of any good cells that have already been infected. White blood cells work with the spleen, which filters out microbes and removes destroyed red blood cells. The spleen also makes antibodies, which help fight off various illnesses by producing a multitude of proteins and chemicals. 

The immune system exists and communicates throughout the entire human body. When a pathogen is released inside the body, the immune system detects it and sends out a signal to the rest of the body to prepare to fight off the harmful microbes.

The immune system is very complex and can adapt to new infections. Our bodies can gain immunity through both passive and active immunity. Passive immunity is not developed by our own bodies and consists of antibodies that get passed down genetically, through breastfeeding, or through immunoglobulin treatments. Active immunity, on the other hand, occurs when our bodies develop immunity over time through the immune system. When the body is exposed to a disease and proceeds to fight it off, it is then prepared to fight that disease with antibodies next time it enters the body.

So, next time you get sick, remember that a very important part of your body is working hard to help you feel better!