Stress-Response
Background--Defense against pathogens
The body has two systems to defend against pathogens, or infectious agents:
nonspecific defense system
- this system nonspecifically attacks all types of pathogens--viruses, viral-infected cells, bacteria, and other foreign agents
- this system is also mediates inflammatory response that occurs in response to an infection or an injury
- this system includes: skin, mucous membranes (pH and enzymes), white blood cells, complement (serum proteins)
- WBCs: neutrophils and macrophages phagocytose pathogen and dead or dying cells
- WBCs: natural killer cells (NK cells) kill virus-infected cells and tumors (damage to cell membranes leading to cell lysis)