What is the immune system?
Humanity has been around for a long time. Today, medical technology has advanced tremendously, allowing people to overcome many diseases. But what was it like in the past? How did people fight against various diseases in the past? The answer is the human immune system. The immune system refers to the body’s ability to fight against external viruses, bacteria, etc. In other words, it is an important function of the body to prevent infection from outside invaders. The immune system can also be said to be a vast network of cells, organs, white blood cells, and proteins throughout the human body. If the protective system had not existed, humanity would not have been able to exist until now.
Types of human immune system
The human immune system can be classified into some types according to its function and role. The following are the immune systems that humans have:
- Innate immunity – It is an instinctive immunity that a person is born with. It is the inherent immune system protects the body from infection with a fast immune response when external harmful substances invade the body. The skin is a human body part that functions as a representative innate immune function. The skin prevents external harmful substances from entering the body. In addition to the skin, the human body parts that act as innate immunity include the nose, neck, body hair, and eyelashes. These parts serve to prevent intrusion from external pathogens.
- Active immunity – It is a type of immune system in the body that gets triggered and works when it comes into contact with harmful substances from outside. Humans constantly contact pathogens even when doing basic activities. Thanks to the active immune system, humans can work without getting sick. Cells with active immunity exist in a small number in our body, and when external harmful substances enter our body, the number of immune cells increases and signals other body organs.
- Passive immunity – Unlike active immunity, passive immunity refers to an immune system created from external sources, not from one’s own immune system. Apart from active immunity that continues to exist in the body, this type of immunity has a short lifespan if it is not continuously supplemented from the outside. A typical example of passive immunity is when a newborn intakes breast milk to obtain immune antibodies. Through breast milk, newborns form antibodies that protect the stomach.
- Adaptive immunity – Adaptive immunity is created when a person is exposed to a disease or is vaccinated. It is activated when pathogens that cannot be treated by the innate immune system penetrate into the body. When one first gets infected with a particular pathogen, it takes a relatively long time for the corresponding immune system to form, which also means the need for a long recovery time. Second exposure to the same disease reduces recovery time because the corresponding adaptive immunity already exists in the body.
How does the immune system work?
The human immune system always works to maintain a healthy body condition. The immune system prevents harmful substances from entering the body. It destroys or prevents the pathogens from spreading when it enters the body. The successful operation of the immune system begins by distinguishing between harmful substances from the outside and immune components in the body.
If the right immune system works, it identifies harmful substances that have invaded from the outside, forms antibodies, and attacks the harmful substances or viruses. In addition, if antibodies are not formed to correspond to the invading pathogen, they are formed (a process of adaptive immunity) after learning about the bacteria. The reason people are vaccinated is to have a process of forming antibodies to diseases.
In the case of people whose immune system does not function properly, antibodies are formed without the invasion of pathogens, which can cause autoimmune diseases. Moreover, if the human immune system does not work properly, the antibodies will continue the attack even after the pathogen that has invaded the body has died. It can cause various side effects in the body, such as many different kinds of allergic reactions.
Conclusion
The immune system is essential for maintaining life. Healthy people have strong immunity that works properly. However, some people have weakened immunity due to health problems and/or certain drugs used to treat certain diseases. People with such weak immunity may need to go to and get advice from a doctor, choose a proper diet and exercise, and put those into their lives.
References
Cleveland Clinic (2020). Immune System: Parts & Common Problems. [online] Cleveland Clinic. Available at: https://my.clevelandclinic.org/health/articles/21196-immune-system [Accessed 1 August 2022].
Hirsch, L. (2019). Immune System (for Parents) – Nemours KidsHealth. [online] kidshealth.org. Available at: https://kidshealth.org/en/parents/immune.html#:~:text=This%20protection%20is%20called%20immunity [Accessed 1 August 2022].
Newman, T. (2018). The Immune system: Cells, tissues, function, and Disease. [online] www.medicalnewstoday.com. Available at: https://www.medicalnewstoday.com/articles/320101 [Accessed 31 July 2022].
Sapre, O. (2020). Explore the Different Types of Immunity – BVG Life. [online] BVG Life Sciences Limited. Available at: https://www.bvglife.com/explore-the-different-types-of-immunity/ [Accessed 1 August 2022].
