The immune system consists of a complex network of cells, tissues, and organs in the human body, and it is responsible for protecting the body from infection and substances that may harm the body by identifying and responding to antigens. These substances are found on the surface of harmful objects entering the body.

The immune system eliminates or attempts to eliminate these substances containing antigens on their surface. It should be noted that antigens are found on the surface of living substances entering the body such as alien cells, viruses, fungi, bacteria, or non-living substances such as toxins, chemical substances, and exotic particles.

We should note also that the cells of the human body contain antigens on their surface, but the difference is that the immune system recognizes them as natural bodies and not alien, and does not activate the immune response process towards them. It should also be noted that the body has several other methods besides the immune system to protect it from the causes of infection. These methods are stated as follows:

The skin

  The skin is a barrier against the entry of water and pathogenic bodies and produces antibacterial oil.



   The lungs secrete the mucus, called sputum, which holds UFOs and nurses, and small bristles called cilia that move the sputum up to be removed from the body by coughing.



  The mucous lining of the gut contains antibodies, and the acid in the stomach kills most germs.

Other defensive methods

This includes body fluids such as tears and saliva, which contain antibacterial enzymes, which in turn help reduce the risk of infection. Also, the natural continuous discharge of the urinary tract and intestines helps protect the body from infection.

The components of the immune system

White Blood Cells

They are a key component of the immune system, manufactured in the bone marrow, and include lymphocytes such as B-Cells, T-Cells, Natural Killer Cells, and other types of immune cells. It is worth noting that white blood cells move in the blood and tissues of the human body, in search of  Pathogens such as bacteria, viruses, parasites, and fungi, to eliminate them if they exist.

It should be noted that the immune system recognizes the antigens we mentioned earlier located on the surface of harmful substances, through various proteins made by a type of white blood cell known as antibodies, whereby each type of antibody recognizes and binds to a particular type of antigen, to identify the harmful substances and stimulate an immune response to eliminate them.

In addition, some antibodies eliminate the harmful substance on which the antigen is located directly on its surface and others stimulate the white blood cells to eliminate them.


The spleen is the largest internal organ of the immune system, and therefore has the largest number of cells in the immune system, where about 25% of the blood coming out of the heart flows accurately into the spleen, and the spleen filters the blood to detect germs. It should be noted that when the presence of bacteria is detected, the cells of the immune system are activated and increased in number to neutralize pathogens.

 Nodes and lymphocytes

 Lymph nodes are tissues filled with immune cells and strategically distributed throughout the body. Some of them may be more commonly known among people than others. For example, most people know that tonsils and adenoids are lymph nodes or glands found in the neck. But they do not know Peyer’s Patches which are lymph nodes found in the intestines. There are many other unnamed lymph nodes that are widespread in the human body.

 Bone marrow

Bone Marrow

 It is a spongy tissue found inside the body’s bones and represents the manufacturing site of white blood cells, as well as the red blood cells the body needs to carry oxygen, platelets that the body needs to clot blood.

Zaatari gland

The Zaatari gland is an important lymphatic organ, found in front of the trachea, where it filters and monitors blood components. In addition, immature T lymphocytes, (a type of white blood cell) after being manufactured in the bone marrow, move to the thyme gland to mature there.

Types of immunity in the human body

 There are three types of human immunity: natural immunity, acquired immunity and borrowed immunity.

Natural immunity

 All people are born with natural or innate immunity, a type of general protection for humans. For example, the skin which acts as a barrier that prevents the entry of germs into the body, and helps the immune system to identify some of the objects that invade the body.  as being strange, and, maybe, dangerous.

Acquired Immunity

It is the immunity that a person acquires and develops overtime during his life and protects him from germs. The immune system makes a variety of antibodies to different germs when first exposed to them, and then the antibodies attack any of these germs if they enter the body again. In other words, the immune system remembers its former enemies and eliminates them through antibodies that recognize them.


Passive Immunity

The human body borrows this type of immunity from another source. But this sort of immunity does not last forever. For example, the fetus in the womb of its mother receives antibodies from the mother through the placenta, and through breast milk during lactation. The borrowed immunity helps protect the child from certain types of infection during the early years of his life.



This is usually acquired through vaccines and done by injecting an antigen into a germ or a weak germ in the body. In this way, a person does not get sick, but his immune system produces antibodies that recognize this specific type of bacteria, to eliminate them if the body is exposed to them in the future.

Immune system diseases

These include the types of different diseases that can affect the immune system:

Immunodeficiency or vulnerability

 Immunodeficiency may be a temporary or permanent condition, where temporary immunodeficiency can occur when exposed to certain factors that weaken immunity such as pregnancy, and the use of certain types of immunosuppressive drugs.

Also, common infections like mononucleosis and influenza can temporarily weaken the immune system. On the other hand, some other types of infection, such as HIV which causes AIDS, can cause severe and permanent weakening of the immune system and destroy the T-cells in it, making the body vulnerable to various infections.

Other examples of diseases that cause permanent immunodeficiency diseases are primary immunodeficiency diseases. These are genetic disorders in the immune system in which the child has been infected since birth. Although there are more than 150 different types of these diseases, they are considered as rare.

Autoimmune Diseases

  It accidentally attacks the body’s natural and healthy tissues. No one knows exactly the cause of this disease. But it may be a combination of genetic and environmental factors. Common types of autoimmune diseases are rheumatoid arthritis, diabetes type 1, and lupus.  

Hyperactivity of the immune system

This happens when a person is born with certain genes that cause the immune system’s response and the body’s sensitivity to environmental substances that are usually harmless such as dust, pollen, and some foods. These substances are called allergens. Some of the most common examples of hyperactivity disease are the various types of allergies suffered by some individuals. It is worth noting that asthma, eczema, allergic rhinitis, and food allergy are also caused by hyperactivity of the immune system.

Strengthening the immune system

 It should be noted that it is difficult to know how to strengthen the immune system for several reasons. The first of which is that it is a system that consists of several parts which must work in balance and harmony in order for the system to work efficiently. Researchers still do not know much about the complexities and interdependence of the immune response.

More than that, scientists have not yet been able to provide scientific evidence of the relationship between an individual’s lifestyle or system and enhancing the efficiency of the immune system. But they are still studying the impact of lifestyles such as healthy food, exercise, psychological stress, and other factors on the immune response of humans and animals. Till then, we can follow healthy life strategies which, in general,  may have a role in strengthening and enhancing the immune system. Some of these strategies are:

 Choice of whole and unprocessed foods

This includes foods that may help to strengthen and enhance the immune system such as garlic, foods rich in vitamin C, fruits and vegetables rich in antioxidants especially berries and spinach, as well as prebiotics such as artichokes and bananas, which help boost beneficial gut bacteria.

 Healthy Foods

Get a good amount of sleep

A person needs to get a good amount of sleep estimated at about 7-8 hours per night to enhance his body’s health and immunity.


Five minutes of guided meditation, or sitting quietly and focusing on breathing deeply, can make a difference in a person’s health.


Exercise increases a person’s flexibility and may increase the body’s efficiency in fighting infection. Besides, different human body organs work more efficiently if the individual engages in physical activities on a regular basis.

Taking nutritional supplements

Some supplements that can be obtained from pharmacies may help boost immunity such as vitamin B6, vitamin C, vitamin E, and vitamin D which is important for the functioning of the immune system. Many people suffer from vitamin D deficiency, so sun exposure is recommended for these people to get the needed amount of vitamin D. If vitamin D level is found to be low, it is advisable to take vitamin D supplements or tablets.

Using of some types of essential oils

Some oils contain antiviral properties, while others have a calming effect. As an example, we can state eucalyptus oil and tea tree oil. Some essential oils may therefore help protect people from infection with viruses and help relieve anxiety and improve sleep.

The impact of aging on the immune system

Deficiency in the immune system

The immune system becomes incapable of distinguishing between normal body cells and foreign substances, making older people more vulnerable to autoimmune diseases.


These are types of immune cells whose function is to eliminate certain types of bacteria, cancer cells, etc. But, with age, they may work inefficiently. This, as a consequence, may contribute to an increase in cancer and other types of infection among the elderly.

Slow response of T-cells to antigens

Lymphocytes that respond to bacterial infection become fewer and slower.

Insufficient immune system’s response

The possibility of producing an incomplete immune response to bacterial infection in old age.

The lack of antigen susceptibility

Although the number of antibodies in the body is not significantly lower with age, age may contribute to a lack of association between antibodies and antigens through which the immune system recognizes infectious substances. This may contribute to an increase in cases of pneumonia, influenza, and tetanus. Ther is an increased risk of death from these types of infections among older persons. This is why vaccines are less effective in older people.


I am not a doctor, psychiatrist, therapist, or professional, and I don’t play one on the internet. So the information provided herein is for informational purposes only and does not constitute professional advice. Plus, before taking any decision based on what you find on this website, you are advised to consult a doctor or professional.

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