Immunity 4 MIN READ 1711 VIEWS March 21, 2022

Understanding the Immune System: How It Works

Immune System

The body is under constant attack and pressure from outside forces, including viruses, bacteria, toxins, fungi and even parasites. But for the most part, we don’t really see the effects of these microscopic invaders. Why is that? It’s because the parts of your immune system (including the innate and adaptive immune system) are working together to keep these pathogens in check. How does the immune system work and what are the important facets of it? Let’s find out.

Parts of the Immune System Explained

Let’s start with the parts of the immune system and what they do:

1. Skin

Your skin is the first line of your immune system. It is a physical barrier since the skin is not easily breached. Not only does it behave like a wall for microbes but it also releases proteins that can discourage the growth of pathogens. Additionally, within certain layers of skin, immune cells are waiting for the lucky few microbes that do get through. Since the various bacteria and germs get through any opening they find, it is very important to disinfect any breaks in your skin (such as from scratches or cuts). 

2. Bone Marrow

You may not know this but the bone marrow is where most of the cells of the innate and adaptive immune systems are created. The bone marrow is the production site for many important cells in your body, starting with stem cells that can turn into specific cells later on. These include: 

Neutrophils: a type of white blood cell that kills and eats pathogens. These are the most abundant type of white blood cell and are part of the innate immune system

Basophils: they release enzymes that attack bacteria and other pathogens. These are also part of the generalized innate immune system.

Dendritic Cells: they act as the messenger between the innate and adaptive immune systems. These cells inform your killer T cells of what exactly they need to look for in the invaders. 

Macrophage: it surrounds, destroys, and clears out dead or dying cells. These macrophages can also be the reason you get a fever since they signal strongly to the body, which in turn, causes inflammation.

B and T cells: they are highly specific cells that can attack very specific antigens. They are the heroes of your adaptive immune system. These cells require more time to react since they are specific in what they target.

3. Blood

The blood is like your immune’s public transport system. All the white blood cells in your body (including those mentioned above) are able to circulate the entirety of your organs through the bloodstream. We can get a good idea of how active the immune system is by taking a sample of blood, this is why blood tests are so important. 

4. The Lymph Nodes

The lymph nodes and system act as vessels for your immune system. The lymphatic system is able to pass cells and information between your organs and bloodstream. This makes it a perfect reservoir for a lot of your immune system cells to converge in. The presence of the lymph nodes across the body means that when a pathogen is detected at some distant organ, the immune cells receive the information and leave the nodes. They begin hunting down the invader as quickly as possible.

5. Mucosal Tissues

The mucosal tissue occurs at any entry point from where bacteria may get through to the inside of your body easily. This includes points of entry like the nose, mouth, and stomach. Immune system cells are present in these spots; always keeping an eye out for invaders that try to enter your body. 

About the Types of Immunity

You may have noticed that we distinguished between different types of immunity here. That is because the immune system is far more complex than we initially thought. It is made up of several types: 

  1. Innate Immune System: This is what you are born with. It is a general, all-purpose reaction against any kind of pathogen or toxin entering the body. This includes the skin and general immune system cells which attack anything they assume is not part of your body. 
  2. Adaptive Immune System: This is the more specialized and targeted part of your immune system. It learns to recognise specific invaders and produces the specific proteins to destroy that invader. But it takes time to work; hence, your innate immune system starts working immediately while the adaptive immune system is still figuring out how to kill the invader.
  3. Passive Immune System: This is when you get immune protection from some outside sources. This can be from blood plasma transplants or more commonly, it occurs from mother to child. When the child is in the womb, they do not produce their own immune cells; the mother’s immune cells can transfer to the child through the placenta. 


This is an overview of how most of the immune system works; the details are much more complex and wondrous! For example, some people may not produce enough white blood cells, which often leads to a weak immune system. At other times, people suffering from an infection may require help through the use of medicine. Either way, we need to keep our body and immune system in top form to be able to handle infections with resilience.

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