The Body's System of Self-Defense
The human body has many defensive tactics; continuously working to eliminate materials potential pathogens from its territory. Our body must defend itself from detrimental bacteria, viruses, fungi, protozoans, parasitic worms and even its own cells gone awry, in the case of cancer.
To more easily understand how our body polices itself, it is convenient to divide these tactics in three categories, the first, second and third lines of defense.
The immune system's first and second lines of defense are nonspecific, operating in a generalize type of way rather than in direct relation to the intruder.
Our body’s first line of defense includes structures, and chemicals, processes that work to prevent pathogens entering the body. These include the skin and mucous membranes of the respiratory, digestive, urinary, and reproductive systems.
Second Line of Defense
Blood
Blood is composed of plasma, the liquid portion of blood, and formed elements, the solid components of blood, including red blood cells, white blood cells (leukocytes) and platelets.
See the following links to more detailed information on the immune system's white blood cells.
- leukocytes: intracellular phagocytosis
- leukocytes: extracellular killing of NK cells
Chemicals
- complement system
- interferons
- defensins
Inflammation
Fever
Specific Immune Response
Third Line of Defense
The Players
- Antibodies (immunoglobulins)
- B-lymphocytes (B Cells)
- T-lymphocytes (T Cells)
- Cytotoxic T Cells (TC Cells)
- Helper T Lymphocytes (TH Cells)
The Processes
Humoral Immune Response
- B-Cell Activation
- Memory B-Cells
Cell-Mediated Immune Response
- Cytotoxic Pathways
- Memory T-Cells
Development of Science Prof Online Immunology Content
The links above will take you to information on the specific components of the immune system. Science Prof Online web pages covering this complex topic are currently being developed, so as you come back to this area of the site, you will see the number of links above increasing, and changing as more information is added.
 | |||
Sources
Content
Bauman, R. (2005) Microbiology.
Campbell, N. and Reece, J. (2005) Biology,Seventh Edition.
Park Talaro, K. (2008) Foundations in Microbiology.
Images
T-Cell and Dendritic Cell: Source lbl.govPBD-immune-system
Macrophage killing canger cells, Susan Arnold.
Yellow Salmonella (color altered in photo), Rocky Mountain Labs, NIH
