the immune system neekoli caulderon, zoë irons, kori mcevoy, matt noel
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The Immune SystemNeekoli Caulderon, Zoë Irons, Kori McEvoy, Matt Noel
The Purpose of the Immune System• Prevent the entry of
pathogens or • Destroy them as they
enter via innate (nonspecific) defenses or adaptive (specific) defenses
• Pathogen: disease causing agent including viruses, bacteria, fungi, & protozoans
Nonspecific Defenses
Mechanical Barriers
Physical barriers
Mucous membranes
1st line of defense
Chemical Barriers
Stomach acid (pepsin & HCl)
Salt in sweat
Interferons (respond to viruses/tumor cells)
Complement (group of proteins in bodily fluids that interact in a series of reactions that stimulate inflammation, attracts phagocytes & enhances phagocytosis)
Leukocytes- White Blood Cells
Move in/out of capillaries via diapedesis
Lymphocytes: T-Cells, B-Cells, NK Cells
Phagocytes: cells that eat invading cells
Neutrophils: phagocytes that can move around quickly but immediately die after eating a cell and turn into pus
Macrophages: phagocytes that don’t move around quickly but can eat more than neutrophils; also detect cancerous cells
Natural Killer (NK) Cells
Different from those that provide specific defenses
Defend the body against viruses and cancer cells by secreting cyclotic (cell-cutting) substances called perforins
Cause inflammation
Inflammation and Phagocytosis
Inflammation
Response to injury/infection
Localized redness, swelling, heat, pain
Result of blood vessel dilation and
Edema: increase in capillary permeability
Phagocytosis
Performed by phagocytes
which are attracted to chemicals released by injured tissues
Powerful mechanism that effectively destroys a lot of pathogens before we know they’re there
Fever
Elevated body temperature
Causes liver and spleen to store iron, reducing its level in the blood
Bacteria and fungi require more iron as temperature rises, so their growth and reproduction is slowed
Phagocytes are more active at a higher temperature
Not always meant to be treated with a lot of medication
Specific/Adaptive Immune System
Immunity
3rd line of defense against pathogens
Built up slowly over time
Resistance to specific pathogens or to other toxins
Cells
Lymphocytes and macrophages that recognize & remember specific foreign molecules
Antigens/Antibodies
Antigens
Incite the production of antibodies & the immune response
Come from invading pathogens
Molecule or protein given off by pathogens
A chemical fingerprint
Antibodies
AKA Immunoglobulin
Produced by memory B cells that recognize the antigen
Y-shaped
Bind with specific antigens, tagging the pathogen for elimination
Lymphocytes
T Cells
Mature in the thymus
Have no antigen-presenting properties
Rely on B cells to mark a pathogen w/ antigens
70-80% of lymphocytes
B Cells
Immature cells produced in bone marrow, become transitional B cells before maturing
Produce antibodies that destroy antigens/antigen-bearing agents
20-30% of lymphocytes
Types of T Cells
Cytotoxic T Cells
Kill cells infected with a virus (apoptosis)
Kill (potential) cancer cells
Have been linked to organ transplant rejection
Memory T Cells
Present in blood stream for an extended duration after the infection has subsided
React quickly to a triggering antigen upon re-exposure
Cytotoxic T Cells
The End
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For Now