The Immune System: Definition, Characters, Functions, 3 Types, Worst Food and More

the immune system

For human survival, especially post covid, our immune system is critical. Our body would be exposed to bacteria, viruses, parasites, and other pathogens if we didn’t have an immune system. As we travel over a sea of germs, it is our immune system that keeps us healthy.


“The bodys immune system is like any other system of the body. Each of them have their vital function for the human host..”

Anthony S. Fauci

What is the Immune System?

It’s a complex network made up of a variety of cells, organs, proteins, and tissues that are spread throughout the body. It can also tell the difference between our tissue and foreign tissue – self and non-self. It also recognizes and eliminates dead and defective cells.

The Main Characters of the Immune System

When the immune system comes into contact with a pathogen, such as a bacterium, virus, or parasite, it mounts an immune reaction. We’ll explain how this works subsequently, but first, let’s examine some of the important characteristics.

White blood cells

Leukocytes are another name for white blood cells. They travel through the body in blood vessels and lymphatic channels, which run parallel to the veins and arteries.

White blood cells are always on the lookout for infections. They multiply when they discover a target and relay signals to other cell types to do the same.

Our white blood cells are stored in lymphoid organs, which are located throughout the body. The following are some of them:

  • Thymus — a gland between the lungs and just below the neck.
  • Spleen — an organ that filters the blood. It sits in the upper left of the abdomen.
  • Bone marrow — found in the center of the bones, it also produces red blood cells.
  • Lymph nodes —small glands positioned throughout the body, linked by lymphatic vessels.

There are two types of leukocyte:

1. Phagocytes

Pathogens are surrounded by these cells, which absorb them and break them down, effectively consuming them. There are a variety of them, including:

  • Neutrophils — these are the most common type of phagocyte and tend to attack bacteria.
  • Monocytes — these are the largest type and have several roles.
  • Macrophages — these patrol for pathogens and also remove dead and dying cells.
  • Mast cells — they have many jobs, including helping to heal wounds and defend against pathogens.

2. Lymphocytes

Lymphocytes help the body to remember previous invaders and recognize them if they come back to attack again.

Lymphocytes begin their life in bone marrow. Some stay in the marrow and develop into B lymphocytes (B cells), others head to the thymus and become T lymphocytes (T cells). These two cells in the immune system have different roles:

  • B lymphocytes — they produce antibodies and help alert the T lymphocytes.
  • T lymphocytes — they destroy compromised cells in the body and help alert other leukocytes.

What are the 3 major functions of the immune system?

We wouldn’t be able to combat hazardous items that enter our bodies from the outside or detrimental changes that occur inside our bodies if we didn’t have an immune system. The immune system’s primary functions are as follows:

  • to combat disease-causing microorganisms (pathogens) such as bacteria, viruses, parasites, and fungi and remove them from the body
  • – to recognize and neutralize hazardous substances in the environment
  • – to combat disease-causing alterations in the body, such as cancer cells

Types of Immune Systems

In humans, there are three types of immunity: innate, adaptive, and passive.

innate immune system: All of us are born with some level of resistance to intruders. Humans, like those of many animals, will immediately attack alien intruders. The external barriers of our body, such as the skin and mucous membranes of the throat and gut, serve as the first line of defense against viruses. This is a more generic and non-specific reaction.

Adaptive Immunity: The adaptive immune system protects from pathogens that develop as we go through life. As we are exposed to diseases or get vaccinated, we build up a library of antibodies to different pathogens. This is sometimes referred to as immunological memory because our immune system remembers previous enemies.

Passive Immunity: This kind of immunity is “gotten” from somewhere else, but it doesn’t endure forever. An infant, for example, acquires antibodies from the mother through the placenta before delivery and through breast milk afterward. During the early years of a child’s life, this passive immunity protects them from some infections.

The Common Disease/Disorders of the Immune System

The immune system may produce antibodies that, instead of defending against infections, attack the body’s own tissues in reaction to an unknown stimulus. The goal of autoimmune disease treatment is to reduce immune system activity. Autoimmune disorders include the following:

  • Type 1 diabetes. The immune system attacks the cells in the pancreas that make insulin. Insulin removes sugar from the blood to use as energy.
  • Rheumatoid arthritis. This type of arthritis causes swelling and deformities of the joints. An auto-antibody called rheumatoid factor is in the blood of some people with rheumatoid arthritis.
  • Lupus. This disease that attacks body tissues, including the lungs, kidneys, and skin. Many types of auto-antibodies are found in the blood of people with lupus.

Worst Food Ingredient: There are certain food ingredients that cause a weakened immune system. A number of them are listed below:

White Sugar: You’re in for some trouble if you’re a sweet lover. The worst food for your immune system is white sugar, also known as refined sugar.

White sugar is abundant in foods such as candies, chocolates, cakes, donuts, biscuits, and other desserts. Sugar is disguised in meals like tomato ketchup, fruit drinks, cereals, bread, and pasta.

Fried Foods: If you enjoy fried foods, it’s time to cut back on your oil consumption. Deep-fried foods are high in grease and fat, and they are known to lower immunity. To satisfy your hunger, choose roasted, sautéed, baked, or air-fried foods over deep-fried items.

Alcohol: While occasional drinking may not be harmful to the body, if you are a chronic drinker who consumes alcohol on a daily or even weekly basis, you should be aware that your favorite glass of liquor is lowering your immunity. Regular alcohol drinking can have a negative impact on immunity, as well as disrupt sleep, cause obesity, harm liver function, and even harm the heart.

What is Immunity?: This is the ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitized white blood cells.

  • Everyone’s immune system is unique, but it tends to become stronger as we get older since we’ve been exposed to more diseases and gained more immunity.
  • As a result, teens and adults get sick less frequently than children.
  • When an antibody is made, a copy is stored in the body so that if the same antigen is encountered again, it can be dealt with more swiftly.
  • That is why some infections, such as chickenpox, only affect you once since your body has a chickenpox antibody on hand, ready to eliminate it the next time it appears. 

Immunizations: An immunization introduces antigens or weakened pathogens to a person in such a way that the individual does not become sick but still produces antibodies. Because the body saves copies of the antibodies, it is protected if the threat should reappear later in life.

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