Immune Organs - organs of the immune system

The immune system is composed of different immune organs, cells and tissues. For now, let’s see which immune organs(and tissues) make up the immune system and then move on to the cells. Why? Because, this way, we keep it short and it is easier to understand if we take it step by step.

My intention here is to break the subject down as nicely as possible, avoiding confusion at the same time. So, before we even start moving forward, it is necessary to make a clarification and make sure we have this clear:

• There are several different systems in the human body – nervous system, blood system, immune system, digestive system and so on.

• Occasionally, one system can engage in another or there can be overlapping between them.

• The lymphatic system is portion of the body's defense mechanisms. It takes on a huge role within the body's protection from an infection plus some other disease, like cancer.

• Because the lymphatic system is portion of the body's defence mechanisms, it is actually safe to make reference to one or another yet still stay on track and make sense of what we mean.

• The lymphatic system (just like the blood system), is portion of the circulatory system and yes it exists in parallel with the blood system, but has a fluid known as lymph, instead of blood.

• It generates and assists to handle materials - cellular material, protein, nutrition, waste material




In t the literature we find two groups of immune organs (or lymphoid organs as it is also part of the lymphoid System):


"Primary organs” - These are immune organs concerned with production and maturation of lymphoid cells and including bone marrow and thymus gland.

“Secondary organs” - these immune organs are spots or sites in which the lymphocytes localize, identify unfamiliar antigens and triggers reaction in opposition to it. It Contains tonsils , lymph nodes, Spleen, Peyer’s patches ( in the small intestines), appendix and liver.


Note: you may find bone marrow, thymus gland, spleen and lymph nodes in the same group (primary organs)- it depends on the author, the book and the importance of the role an specific organ plays in the immune system in that given context.

Talking about the immune organs (i'll get back to the immune system cells later):




Primary Organs:


Thymus- located beneath the breast bone. Those two lobes! It functions at its peak during adolescence producing specialized lymphocytes-T-cells and B-cells and dispatching them through lymph vessels to secondary organs. In very simple words, we can say its purpose is to initiate antibody formation

Immature thymocytes, also called prothymocytes, abandon bone marrow to move in to the thymus. By way of an extraordinary maturation process at times called thymic education, T cells which are good for the body's defense mechanisms are spared, but other T cells which may stimulate a harmful autoimmune reaction are eliminated. The Release of Mature T cells into the bloodstream takes place next.

It all sounds complicated, i know! but keep in mind "thymus' role is to process lymphocytes, which are white blood cells".




Bone Marrow - I cannot stress enough how important the bone marrow is since All Of The CELLS from the immune system, before anything else, are originally produced by the bone marrow. They are formed via a process named hematopoiesis. Throughout hematopoiesis, the stem cells derived from the bone marrow separate into either into precursors of those cells that travel from the bone marrow to carry on their growth somewhere else or into mature cells. Bone marrow generates B cellular material, granulocytes, natural killer cells, and also immature thymocytes, as well as red blood cells.




Secondary Organs:

Lymph nodes- Also at times termed as lymph glands, they are little spherical or bean-shaped clusters of lymphatic tissues enclosed by a sort of capsule made of connective tissue. There are about 500-700 lymph nodes spread all through our bodies. Lymph nodes separate out the lymphatic fluid the store specific cellular material that will capture most cancers cells or bacterias which are travelling throughout the human body within the lymph fluid.




Spleen - just about one of the most essential of the immune organs, it works as an immunologic filtration system in the bloodstream. It consists of B cells, dendritic cells, T cells, red blood cells, macrophages and natural killer cells . Together with catching unfamiliar materials (antigens) from your bloodstream that goes by dendritic cells, spleen, migratory macrophages and deliver antigens on the spleen through the blood stream. An immune answer is started once the dendritic cells or macrophage offer the antigen towards the proper T or B cells. This organ could be regarded as a conference center in the immunological sense . Within the spleen, Then follows the activation of the B cells and the production of massive quantities of antibody. Also, older red blood cells, at that time, are eliminated within the spleen.


Tonsils and adenoids - They are two lumps of tissues, on either sides in the throat, inserted in a pocket beside the palate (that's the roof of the mouth). The low edge of every single tonsil is near the tongue...way at the back of the throat. The adenoids really are a single clump made of tissue behind the nose area (nasopharynx). They're situated (in the adult) around the backside wall structure of the throat (pharynx)...about 1 inch over the uvula (the small teardrop shaped little bit of tissues that dangles down in the center of the soft palate). Even though adenoids and tonsils have comparable purpose, i.e. trapping viruses and bacteria, they're entirely independent immune organs.


Peyer’s patches - the nodules of lymphatic cells that combine to make patches or bundles and appear generally only within the lowest part (ileum) of your small intestine; they're called for that 17th-century Switzerland anatomist Hans Conrad Peyer. Saying that in a different way, they could be thought as patches of nodules, in the small intestiness walls; agminated glands.


Appendix - It's a thin, dead-end tube measuring about three-to-four inches in length and it hangs from the cecum (which is end in the large intestine). Even though it's typically called the "appendix," the actual term for it is "vermiform appendix."

During the past, the appendix was regarded as not having any purpose in the body or as not currently being among the immune organs. Today, it is stated, often, that this takes on a task in the body's defense mechanisms because its surfaces incorporate aggregated lymphoid tissues. researchers say the appendix assists in supporting the immunity process in 2 approaches. It will help tell the lymphocytes exactly where they have to head over to attack infection and it also enhances the massive intestine's defenses to a range of drugs and foods.





i promised to keep it as simple as possible but sometimes the best we can do is still a lot to take!

The video bellow summarizes everything so go ahead and watch it to fully grasp all the definitions we have gone though on this page.

just keep in mind that the cells involved in the immune response are organized into tissues and cells and these structures are collectively referred to as the lymphoid system or lymphoid organs sometimes!








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