Human Immune System: What are the Major Components of the Immune System?

Dr. Rajkumar Vinod Desai

Medically reviewed by

Dr. Rajkumar Vinod Desai

General Physician

4 min read

Key Takeaways

  • The human immune system consists of cells, proteins, and organs
  • Innate and adapted immunity are two major immunity types
  • Stomach acid kills many bacteria that enter the human body

The human immune system is a complex structure of cells, proteins, and organs that defend your body against disease-causing germs. Multiple immune system parts work together against pathogens like bacteria, viruses, fungi, and other foreign invaders. It is key for you to maintain strong immunity as a weak immune system can’t fight aggressive germs that can make you sick [1].

Since your immunity protects you against infections, you should know about its functions, the various immunity types, and the components of the immune system. Learning about the human immune system helps you care for your health better and boost overall immunity. Read on to learn about the different immune system parts. 

Additional Read: Important Symptoms of Weak Immunity and How to Improve It 

Components of the immune system

  •  Antibodies

Antibodies recognize antigens, a substance on the surface of the foreign toxins, and mark them for destruction. As such, they help your body against microbes and other toxins. However, antibodies are disease-specific [2] and each type protects you against specific disease-carrying germs.

  • White blood cells

White blood cells originate in your bone marrow and travel in your body through blood and tissues. They play a major role in identifying foreign invaders like bacteria, viruses, fungi, and initiates an immune attack against them. White blood cells contain many types of immune cells like lymphocytes, B-cells and T-cells.

  • Spleen

The spleen is an organ that filters blood by removing microbes and destroying damaged or old red blood cells. It stores white blood cells and produces components like antibodies and lymphocytes to fight against germs.

  • Bone marrow

The bone marrow is the spongy tissue in your bones that produces red blood cells, white blood cells, platelets, plasma cells, and other immune cells. This spongy center of your bone produces billions of new blood cells each day that are needed by your body.

  • Thymus

The thymus is responsible for producing white blood cells known as T-cells. These memory cells remember and recognize a disease-carrying germ the next time it is encountered by your body. Thus, it helps the human immune system prepare for a quick response.

Boost your immunity 
  • Lymphatic system

The lymphatic system consists of lymph nodes, lymph vessels, and lymphocytes that comprise important immune system parts [3]. These networks of delicate tubes deal with cancer cells, absorb fats, manage fluid levels and attacks bacteria. Lymph glands are present in your armpits, neck, groin, and other parts of your body.

  • Tonsils and adenoids

Tonsils and adenoids imprison germs as soon as they enter your body [4]. They protect you against bacteria or viruses that can cause throat or lung infections by producing antibodies.

  • Stomach and bowel

The acid in your stomach kills many bacteria when they set foot in your body. The intestines also have good bacteria that help in killing harmful bacteria. Therefore, the stomach and bowel system form important components of the immune system.

  • Skin and mucous membranes

Your skin acts as the first line of defense against germs by producing oils and other defensive immune cells. A mucous membrane covers the surface of internal organs and

lines various cavities and canals in the body that lead to respiratory, digestive, and urogenital tracts. The membrane emits mucus that moistens and lubricates surfaces. The infectious substances stick to the mucus and are then removed through the airways in your body.

Tips to build immunity

Immunity Types

  •  Innate immunity

Innate immunity is the inborn immunity you are born with. It acts as the first line of defense against harmful pathogens. Skin, hair, and mucous membranes are some examples.

  • Adapted immunity

Adapted or acquired immunity is the second line of defense that attacks pathogens. This type of immunity creates antibodies that are specific to certain disease-causing germs. Examples of adapted immunity include swelling, pain, pus, T-cells, and B-cells response.

The function of human immunity system

The primary function of the human immune system is to defend your body against pathogens that cause disease and infections. Your immune system also neutralizes any harmful substances from the environment by recognizing them. It also fights against harmful changes in the body including cancer cells.

Additional Read: What are the Best Vitamins and Supplements to Boost Immune System?

With the workings of the immune system explained above, you now know how this complex mechanism plays a role in boosting your overall health. Keep your immune system healthy by getting enough sleep, maintaining optimal weight, reducing stress, and following a healthy diet and lifestyle. A regular health check should be a part of your healthcare routine. Consult with the best doctors by booking an in-clinic or virtual appointment on Bajaj Finserv Health to get proper guidance on your health and immunity.

Published on 2 Sep 2021Last updated on 5 Apr 2023

Please note that this article is solely meant for informational purposes and Bajaj Finserv Health Limited (“BFHL”) does not shoulder any responsibility of the views/advice/information expressed/given by the writer/reviewer/originator. This article should not be considered as a substitute for any medical advice, diagnosis or treatment. Always consult with your trusted physician/qualified healthcare professional to evaluate your medical condition. The above article has been reviewed by a qualified doctor and BFHL is not responsible for any damages for any information or services provided by any third party.

Dr. Rajkumar Vinod Desai

Medically reviewed by

Dr. Rajkumar Vinod Desai

, MBBS 1


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