IMMUNE SYSTEM

Articles in English

The immune system is probably the most important system in the human body. It was designed by nature millions of years ago to aid the body in recovering from injuries and illnesses. The immune system is a complex of organs, all of which work together to clear infection from the body. The organs of the immune system, positioned throughout the body, are called lymphoid organs. The major parts of immune system are the thymus, spleen, lymph system, bone marrow, white blood cells, antibodies, and hormones. Lymphatic vessels and lymph nodes are the parts of the special circulatory system that carries lymph, a transparent fluid containing white blood cells, chiefly lymphocytes. Although we inhale and eat thousands of germs every day, the immune system prevents them from causing the diseases. Human body has many mechanisms

The Work of Immune System

that defend the person against infectious organisms. The skin and gastrointestinal tract are the first lines of defense. The human organism has a specific capacity of resistance against infection called immunity. There are two general categories of immune mechanisms: humoral and cell-mediated.

Humoral immunity is based on certain body proteins called antibodies, which are found dissolved in the blood and other body fluids. The antibodies are made by plasma cells, which are derived from certain white blood cells called B lymphocytes (or B cells). The antibodies are produced in response to exposure to a foreign substance. Any foreign substance that enters the body and causes the manufacture of antibodies is called an antigen.

Cell-mediated immunity is based on the actions of phagocytes and other white blood cells. Phagocytes are cells that can dissolve or engulf and destroy viruses, bacteria, fungi, and cells foreign to the body. White blood cells that are involved in this defense are a type of lymphocyte called T cells because they are derived from the thymus gland.

Agents that can invade the human body live everywhere. The majority of these organisms do not produce disease, but some do. The basic types of organisms that cause infectious disease are bacteria, viruses, fungi, protozoa, and helminths.

Possible help for the immune system is a healthy diet, with lots of natural sources of vitamins A, C and E, zinc, iron, and vitamin B₆.