TRUTH ABOUT IMMUNITY | LEARN EVERYTHING ABOUT IMMUNITY

What is the immune system?




This network of tissues, cells, and organs first tries to keep out germs like bacteria, viruses, fungi, and parasites and then deals with them if they manage to get in. The immune system protects the body against disease or other potentially damaging foreign bodies. If it senses something in your body that could be bad for you, it triggers the release of special cells. These travel to where the trouble is, attack the intruder, and help get rid of it.


Our immune system is essential for our survival. Without an immune system, our bodies would be open to attack from bacteria, viruses, parasites, and more. It is our immune system that keeps us healthy as we drift through a sea of pathogens.


The immune system is spread throughout the body and involves many types of cells, organs, proteins, and tissues. Crucially, it can distinguish our tissue from foreign tissue — self from non-self. Dead and faulty cells are also recognized and cleared away by the immune system.

If the immune system encounters a pathogen, for instance, a bacterium, virus, or parasite, it mounts a so-called immune response.



How Do Infections Spread?

Your body has to be able to stop invaders that come from a lot different places. Germs can come from contact -- touching skin, having sex, and breathing in drops from someone else's sneeze or cough, for example. They can travel through blood that comes from a shared needle or an insect bite. You can also get germs from contaminated food or water.

There are two main parts of the immune system:

The innate immune system, which you are born with.

The adaptive immune system, which you develop when your body is exposed to microbes or chemicals released by microbes. These two immune systems work together.



The innate immune system We are all born with some level of immunity to invaders. Human immune systems, similarly to those of many animals, will attack foreign invaders from day one. This innate immunity includes the external barriers of our body — the first line of defense against pathogens — such as the skin and mucous membranes of the throat and gut. This response is more general and non-specific. If the pathogen manages to dodge the innate immune system, adaptive or acquired immunity kicks in.


The acquired immune system

This protect from pathogens develops 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.


The acquired immune system, with help from the innate system, produces cells (antibodies) to protect your body from a specific invader. These antibodies are developed by cells called B lymphocytes after the body has been exposed to the invader. The antibodies stay in your child's body. It can take several days for antibodies to develop. But after the first exposure, the immune system will recognize the invader and defend against it. The acquired immune system changes throughout your child's life. Immunizations train your child's immune system to make antibodies to protect him or her from harmful diseases.


Passive immunity This type of immunity is “borrowed” from another source, but it does not last indefinitely. For instance, a baby receives antibodies from the mother through the placenta before birth and in breast milk following birth. This passive immunity protects the baby from some infections during the early years of their life.


The immune system can recognize millions of different antigens. And it can produce what it needs to eradicate nearly all of them. When it’s working properly, this elaborate defense system can keep health problems ranging from cancer to the common cold at bay.

White blood cells White blood cells are also called leukocytes. They circulate in the body in blood vessels and the lymphatic vessels that parallel the veins and arteries White blood cells are on constant patrol and looking for pathogens. When they find a target, they begin to multiply and send signals out to other cell types to do the same. Our white blood cells are stored in different places in the body, which are referred to as lymphoid organs. These include the following:

  • 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 vessel

There are two main types of leukocyte:

1. Phagocytes These cells surround and absorb pathogens and break them down, effectively eating them. 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 cell types have different roles: 1. B lymphocytes — they produce antibodies and help alert the T lymphocytes. 2. T lymphocytes — they destroy compromised cells in the body and help alert other leukocytes.


Everyone’s immune system is different but, as a general rule, it becomes stronger during adulthood as, by this time, we have been exposed to more pathogens and developed more immunity. That is why teens and adults tend to get sick less often than children. Once an antibody has been produced, a copy remains in the body so that if the same antigen appears again, it can be dealt with more quickly.

That is why with some diseases, such as chickenpox, you only get it once as the body has a chickenpox antibody stored, ready and waiting to destroy it next time it arrives. This is called immunity.


Signs You Have a Weakened Immune System

1. Your Stress Level is Sky-High