Stress-Response
Background--Defense against pathogens
The body has two systems to defend against pathogens, or infectious agents:
specific defense system--immune system
- this system attacks substances detected as �foreign� by proliferating cells that either attack the invader directly or produce specific defensive proteins called antibodies that lead to the destruction of the pathogen
- B cells and T cells are lymphocytes that originate in bone marrow; B cells also mature in bone marrow--hence B designation; T cells migrate to, and mature within, the thymus--hence the T designation; the maturation process involves development of immunocompetence--specific cells in both groups can detect unique antigenic regions of bacteria and viruses--capacity for selective destruction of viruses and bacteria
- several types of T cells: helper T cell, cytotoxic T cell, suppressor T cell; one main type of B cell; however, there are a multitude of T and B cells that respond to different antigenic sequences of different pathogens