Information in simple English

What is immune system?

An organism's immune system is a network of vital processes that defends it from disease. The immune system defends us against pathogen and keeps us healthy.

The immune system comprises many cells, organs, proteins, and tissues that are distributed throughout the body. It can tell the difference between our tissue and foreign or alien tissue. The immune system also detects and eliminates dead and defective cells.

When a pathogen, such as a bacterium, virus, or parasite, comes into touch with the immune system, it mounts an immunological response. Everyone's immune system is unique, but it gets stronger as we get older since we've been exposed to more diseases and developed more immunity.


What are the many types of immunity in humans?

These three types of immunity in humans: 

  • Innate immunity includes external barriers to the body
  • Adaptive immunity which is required throughout the life 
  • Passive immunity is borrowed from another source but does not last indefinitely. 

What are the components of the immune system?

To keep the body secure, many cells and organs collaborate.

White Blood Cells

White blood cells (WBC) that are part of the immune system are known as leukocytes. White blood cells are on the lookout for pathogens at all times. They multiply when they discover a target and relay signals to other cell types to do the same. Our white blood cells are stored in lymphoid organs, which are throughout the body.

What are the kinds of WBC?

There are two types of leukocytes:

  1. Phagocytes : break down or later devour invading pathogens.
  2. Lymphocytes : assist the body in remembering and recognising previous intruders.

What are the kinds of phagocytes?

The neutrophil is a type of phagocyte that attacks pathogens. Other types of phagocytes ensure that the body responds to invaders in their own way.

What are the kinds of lymphocytes?

Two cell types are present: 

  • B lymphocytes or B cells: body's defense mechanism; locate their targets and dispatch defences to lock on to them.
  • T lymphocytes or T cells: soldiers; eliminate the invaders discovered by the defense system.

Lymphocytes begin their lives in the bone marrow and either mature into B cells or migrate to the thymus gland to become T cells.