Believe it or not, we are always surrounded by millions of germs. No matter how much hand sanitizer you use, you can never really get rid of the plethora of bacteria living on, well, everything.

Don’t worry though! Your body has an amazing defense mechanism that keeps you from getting sick all the time. It’s called the immune system, which is spread all over your body unlike most other systems that are concentrated in one specific area.

The immune system is broken up into lots of different groups of cells and branches, the most broad of which are the innate and adaptive/acquired systems. As you may have guessed, the innate immune system is something you’re born with and you keep for the rest of your life. The cells that comprise the innate immune system are mainly monocytes (which later transform into macrophages) and neutrophils, and they will always be your body’s first line of defense (these two types of cells belong to a special category called “phagocytes,” which means they fight off bacteria/other pathogens by eating them)!

As for the adaptive immune system, things get a little more complicated. No more cells chowing down on bacteria anymore, this part of the system is much more organized! Since it’s adaptive, none of us are actually born with all the cells that comprise this system; instead they grow and develop alongside you. The cells belonging to the adaptive immune system mostly live in your lymphatic system, waiting to be called into action (these guys are never on the front lines, they only get to work during emergencies). If a problem the phagocytes can’t handle arises, macrophage cells will alert a special kind of lymphocyte, called a dendritic cell. These dendritic cells act as messengers, and their job is to bring out the big guns.

T cells and B cells are both the brains and brawn of the immune system. They work both smartly and effectively to eliminate any threat posed to the body. First up are the T cells, which are split up into three types. Cytotoxic T cells attack using powerful chemicals (which is probably why they’ve been nicknamed “natural killer cells”), and they usually don’t mess with foreign invaders. They like to stay local and take care of diseased or cancerous cells that originated in the body. Next up are helper T cells, and they don’t do much besides get a hold of B cells and tell them to get to work! Finally, there are the memory T cells, which are an extremely important part of immunity. They remember everything there is to know about the current infection so it can be dealt with even faster if it poses a threat again (major aspect of vaccines)!

Now I know what you’ve been thinking, what about B cells? They probably seem like big shots if I’ve saved them for last, right? Well the answer is yes! They have a very big role in immunity! Helper T cells bring them samples of whatever pathogen is plaguing the body so B cells can start producing antibodies. Antibodies are specific proteins that bind to and trap the foreign invaders to make it easier for phagocytes on the front lines to capture and digest them.

As complicated as all this seems, there’s so much more to the immune system; the article was just a brief overview! I would encourage everyone to look more into this amazing system that keeps us alive and fights so hard for us!