Is it true that substances are carried from the blood in capillaries to tissues in a liquid called tissue fluid? What is the extracellular fluid in most tissues is called? What is a tissue fluid?   Tissue fluid is the the fluid that surrounds the bodies cells, or technically it bathes the cells in the body or cleans them.
The most important function of immune system is to defend the body from different disease causing pathogens. Whenever there is pathology in human body, immune system is activated to protect the vital tissues from harm.
The immune system is a complex system of interacting cells whose primary purpose is to identify foreign (ânon-selfâ) substances referred to as antigens. The immune system provides protection from infectious disease by identify most of these microbes as foreign. Helper T-cells (CD4+) are middlemen in the immune response. 2  When they get activated, they proliferate and secrete cytokines that regulate or help effector lymphocyte function. 3  They are known as one of the targets of HIV infection, and the decrease of CD4+ T-cells results in AIDS.