The immune system is a complex network of cells and organs essential for human health. In essence, it protects the body from infectious micro-organisms like viruses, bacteria, and fungi. If these micro-organisms enter the body, the immune system combats them. The world we live in is alive with pathogens and parasites. Our immune system is our defense against them. Sometimes this system requires assistance from medication, but whether actively protecting us from germs or promoting recovery, it is one of the major health systems and is vital for survival.


1. White Blood Cells

Also known as leukocytes, white blood cells circulate all over the body via blood vessels and lymphatic vessels. The lymphatic vessels run parallel to the arteries and veins of the circulatory system. Leukocytes are continuously patrolling for potentially harmful pathogens. If they encounter a target like a virus or a bacterium, they start to multiply. As they multiply, they send out communicative signals to other types of cells involved in combatting pathogens, encouraging them to multiply as well.

white blood cells immune system

R_Type / Getty Images

1 of 10

More on Facty Health


Popular Now on Facty Health


This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.