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What is the immune system?

The immune system is essential for the body’s survival. Without an immune system, our body will be easily attacked by bacteria, viruses, parasites and other harmful agents. The immune system keeps you healthy against thousands of different pathogens.

This system consists of a vast network of cells and tissues that are constantly searching for invaders to attack and eliminate. This system extends throughout the body and involves many types of cells, organs, proteins, and tissues. It is important that the system be able to distinguish our own tissue from foreign tissue. Dead and faulty cells in the body are also recognized and eliminated by the immune system.

Components of the immune system

White blood cells, also known as leukocytes, are key components of the immune system. This cell circulates throughout the body in blood vessels and lymphatic vessels parallel to the veins and arteries. White blood cells are constantly patrolling and looking for pathogens in the body. When they find a target, they will begin to multiply and send signals to other types of cells to eliminate the harmful agent.

White blood cells are stored in different places in the body, called lymphatic organs including:

• Thymus: Gland between the lungs and just below the neck.

• Spleen: The organ that filters the blood on the upper left side of the abdomen.

• Bone marrow: This organelle found in the center of bones helps make red blood cells.

• Lymph nodes: These are small glands throughout the body, linked by lymphatic vessels.

There are two main types of white blood cells, phagocytes and lymphocytes.

Phagocyte

These cells attack pathogens by surrounding, absorbing, and disrupting them. Some types of phagocytes include:

• Neutrophils: This is the most common type of phagocyte that tends to attack bacteria.

• Monocytes:  This is the largest type of phagocyte and plays many roles in immunity.

• Macrophages: This is the “patrol” that looks for pathogens and also removes dead and dying cells.

• Mast cells: They have many different jobs, including helping to heal wounds and fight pathogens.

Lymphocytes

Lymphocytes help the body remember previous harmful pathogens and recognize if they attack again. Lymphocytes are produced inside the bone marrow. Some will stay in the marrow and develop into B lymphocytes, others will go to the thymus and become T lymphocytes. The two types of cells have different roles:

• B lymphocytes: make antibodies and help alert T lymphocytes.

• T-lymphocytes: destroy damaged cells in the body and help alert other white blood cells.

Mechanism of lymphocytes in immunity

The immune system first needs to distinguish between body cells and foreign cells. This does this by detecting proteins found on the surface of all cells, then the system learns to ignore its own proteins.

Antigens are substances that can cause an immune response. In many cases, antigens are bacteria, fungi, viruses, toxins, or it can also be the body’s own cells that are faulty or dead. When the body is invaded, a variety of cells work together to recognize antigens.

B . lymphocytes

When B lymphocytes detect antigens, they begin to secrete antibodies – these are special proteins that block specific antigens. Each B cell produces a specific antibody.

Antibodies are part of a group of chemicals called immunoglobulins, which play many roles in the immune response including:

• Immunoglobulin G (IgG): marks bacteria so other cells can recognize and respond.

• IgM: is responsible for killing bacteria.

• IgA: appears in fluids, such as tears and saliva – the way into the body.

• IgE : protects against parasites and also causes allergies.

• IgD: binds to B lymphocytes to help initiate an immune response.

Antibodies are responsible for locking onto antigens, but not destroying them, but only marking them to help other cells recognize them. The killing is done by other cells, such as phagocytes.

T lymphocytes

There are different types of T lymphocytes including:

• Helper T cells (helper T lymphocytes):   responsible for coordinating immune responses. This cell will have 3 tasks including communicating with other cells, stimulating B cells to make more antibodies and attracting more T cells or phagocytosis to destroy cells.

• Killer T cells (cytotoxic T lymphocytes):  is responsible for attacking other cells, especially against viruses. The mechanism works by recognizing small parts of the virus on the outside of infected cells and destroying those cells.

Classification of the immune system

While everyone’s immune system is different, as a general rule, it becomes stronger as an adult. Because by this point, we have been exposed to many pathogens and developed more immunity. That’s why teenagers and adults tend to get sick less often than children.

Once an antibody has been made, a copy of it will remain in the body so that if the antigen reappears, the disease can be dealt with more quickly.

That’s why with some diseases, such as  chicken pox, you only get infected once because the body has a reserve of chickenpox antibody ready to destroy it the next time it invades.

There are 3 types of immunity in humans including:

1. Innate immunity

All of us are born with a certain level of immunity against harmful agents. The human immune system, similar to that of many animals, attacks pathogens from day one, including the external barriers of our bodies, such as the skin and mucous membranes of the neck. throat and intestines.

If the pathogen overcomes the first line of defense, the innate immune system, active or passive immunity in the body occurs.

2. Active immunity

This immune system helps protect the body from the growth of pathogens. When we are exposed to diseases or are vaccinated, the body builds up a series of antibodies to different pathogens. This is sometimes called immunological memory because our immune system has the ability to remember previous harmful agents.

3. Passive immunity

This type of immunity “borrows” from another source, but does not last forever. For example, a baby receives antibodies from the mother through the placenta before birth and in breast milk after birth. This passive immunity helps protect the baby from certain infections during the first years of life.

In addition to the above three types of immunity, vaccination is also a way to help build the immune system. Vaccination is intended to provide the body with antigens or pathogens (weak enough to cause disease) for the body to make antibodies. Because the body stores copies of the antibodies, it helps to fight specific pathogens and antigens later on.

Immune system disorder

The immune system is very complex, and sometimes an underlying problem can cause it to malfunction or malfunction. There are 3 types of immune disorders including:

1. Immunodeficiency

This condition occurs when one or more parts of the immune system fail to function. Immunodeficiency can be caused by factors including age, obesity, and alcoholism. In developing countries, malnutrition is a common cause or AIDS is an example of acquired immunodeficiency.

In some cases, immunodeficiency can be inherited, for example in chronic granulomatous disease, phagocytosis will not function properly.

2. Autoimmune

In some autoimmune conditions, the immune system mistakenly attacks healthy cells, rather than pathogens or faulty cells. Autoimmune diseases can include celiac disease, type 1 diabetes, rheumatoid arthritis , and Graves’ disease.

3. Hypersensitivity reactions

The immune system overreacts and damages healthy tissue. Anaphylaxis is an example in which the body reacts to an allergen so strongly that it can be life-threatening.

To build a healthy immune system, make sure you exercise regularly, eat a varied healthy diet, and get enough sleep.

The immune system is extremely complex with many processes, but most work in perfect synchrony to protect the body. Therefore, you should build a healthy lifestyle to keep the natural disease prevention mechanism always smooth!

Source: hellobacsi.com