What is the Innate Immune System

What is the Innate Immune System

There are two major parts that hold our immune system. The first is innate, a general defence system and the second is an adaptive- specialized defence system. 

These both systems work in coordination and on different levels to keep the microbes at bay. Both of these require several soluble substances such as proteins like enzymes, antibodies and short amino acids to work properly. They take these substances from the blood and other body fluids. Today, we will learn what the innate immune system is and how it works. Take a look: 

Innate Immune System

The Innate Immune system is the general defence system of our body that works very fast. It ensures to destroy the bacteria or germs on the spot within a few hours after detecting their entry from any wound. As it is a general defence system, not the specialized one, it could not respond to specific pathogens. 


What Does the Innate Immune System Consist Of?

The innate immune system has three important elements: 

  1. The closed surface of the skin and all mucous membranes in the body openings like mouth, nose, windpipe, eyelids, lungs, stomach, intestines, urethra, and urinary bladder,
  2. Different defence cells from the white blood cells, and 
  3. Several vital substances of the body fluids and the blood

How does our Innate System work?

Skin and mucous membranes- are the first line of defence of the innate immune system that creates a physical barrier for bacteria or viruses. They stop them from entering the body. Also, the movements made by the bowel muscles or hair-like structures in the bronchi (cilia) do not let the germs to settle in the body. Chemical barriers like sweat, tear fluid, saliva, urine, defecation and vomiting also expel the microorganisms from the body.

Nonspecific Resistance

Despite several obstacles, if viruses or bacteria make them past the skin or mucous membranes, then the second line of defence starts. At this point, the defence cells (WBCs) of the immune system are activated. 

The two types of defence cells- macrophages, which resides in the tissue, and neutrophil granulocytes, which are found in the blood and tissue are the most effective ones. These cells enclose, ingest and destroy the invaders in the interior. 

Along with defence cells, the soluble protein substances are activated too. The proteins are activated in a chain reaction. A total of 9 different enzymes activate – one enzyme of the first stage alerts the second enzyme of the second stage, and so on. This creates a complement system which quickly makes the defence reaction a lot stronger. It results in an inflammatory reaction where the flow of blood increases causing swelling and redness in the affected area. Sometimes it also causes fever. 

The work of these proteins is to make the microbes more pleasant to the scavenger cells or phagocytes, who eats bacteria or viruses. 

So, at this point, the third line of the defence- adaptive immune system or specific resistance, come into action. It helps the innate defence system and mainly relies on antigens, which are specific substances found in microorganisms. 

The innate immune system responds faster than the adaptive immune system. However, the effect of the adaptive immune response is highly specific and long-lasting.So, here in this article, we get to know about how our innate immune system- the first line of defence- works. Read here, how you can make your immune system strong.

Spread the love
Author: Ahaana Sahay