Lymphatic and Immune System

Resistance is the ability to ward off damage or disease through our defenses. Vulnerability or lack of resistance is termed susceptibility.

The Lymphatic and Immune system consists of fluid called lymph, vessels called lymphatic vessels to transport the fluid, a number structures and organs containing lymphatic tissue, and red bone marrow, where stem cells develop into various types of blood cells including lymphocytes. It assists in circulating body fluids and helps defend the body against disease-causing agents. Most components of blood plasma filter through blood capillary walls to form interstitial fluid. After interstitial fluid passes into lymphatic vessels, it is called lymph (LIMF=clear fluid).

Lymphatic tissue is a specialized form of reticular connective tissue that contains large number of lymphocytes.

The Lymphatic and Immune System has three primary functions

1.    Draining excess interstitial fluid: Lymphatic vessels drain excess interstitial fluid from tissue spaces and return it to the blood.

2.    Transporting dietary lipids: Lymphatic vessels transport the lipids and lipid soluble vitamins (A, D, E and K) absorbed by the gastrointestinal tract to the blood.

3.     Draining excess interstitial fluid: Lymphatic tissue initiates highly specific responses directed against particular microbes or abnormal cells. Lymphocytes, aided by microphages, recognize foreign cells, microbes, toxins and cancer cells and respond to them in two basic ways

a.     In cell-mediated immune responses, T cells destroy the intruders by causing them to rupture or by releasing cytotoxic (cell-killing) substances.

b.     In antibody-mediated immune responses, B cells differentiate into plasma cells that protect us against disease by producing antibodies, proteins that combine with and cause destruction of specific foreign substances.