The immune system is so vital that it underpins our very survival. This article from the National Library of Medicine, and this one from Nobelprize.org, will give you a good overview of its importance in our daily life. Here you can learn in even greater detail about its many components, including many of the complicated interactions between its different cells and tissue types.

Key to the immune system’s success is the lymphatic system. See here to learn more about lymph--the fluid this system carries around--and lymph nodes, which work together to transport, store, and enable communication between immune cells in the body. Speaking of cells, the immune system is packed with an abundance of cell types so that it can carry out a well-orchestrated attack against invaders. Here, you can learn more about leukocytes overall, and the different cell categories they can be split into. Read here to learn more about lymphocytes--including the defensive T-cells and B-cells--and phagocytes, which include macrophages and dendritic cells.

Probably the most fascinating aspect of the immune response is the interaction between immune cells, antigens, and the production of antibodies. Here, you can also read about how these antigens are processed and presented to other cells to inform them of the threat. If you’re interested in learning more about how the immune cells make antibodies, this source explains that process.

The overall immune response can actually be split into two main types: innate immunity, and adaptive immunity. The first describes all the immediate defense mechanisms that come into play within hours of the invaders entering your body. Adaptive immunity, on the other hand, occurs over a longer period of time and is designed to gradually build up your defenses against some threats in order to make you less susceptible next time they strike. This video from the Khan Academy explains, in detail, the different roles that these two types play.

But as we now know, this doesn’t work so well for everyone. Autoimmune diseases are widespread and relatively common: here and here you can read all about these disorders and the many different forms they take.

Keen to learn more? Why not watch this TED Ed video about how cells battle viruses in your body, or this one, which explores the fascinating reasons why you feel uncomfortable, sore, and grouchy when you are sick.

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