The Immune System and Innate Defenses Flashcards
Define a pathogen.
Pathogen: a potentially harmful microbe
Name 3 organs or tissues borrowed from other systems and used for their immune functions.
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What is part of the 1st line of defense? The 2nd? The 3rd?
Innate (Nonspecific) Defense System: always prepared, not highly trained
First Line of Defense: a surface barrier
Second Lind of Defense: internal defenses that act when the 1st line is broken
Adaptive (Specific) Defense System: requires significant training, targets identified foes
Third Lind of Defense: slower to mount but acts with more precision and efficacy
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Name three protective chemicals from the 1st line of defense.
Acid to inhibit bacterial growth
Enzymes (Example: Lysozyme) to destroy bacteria
Mucin to trap microbes
Defensins to control bacterial growth in exposed areas
List the 4 cardinal signs of inflammation.
Redness, Heat, Swelling, and Pain
What purposes does inflammation serve?
Prevent the spread of damaging agents to the nearby tissues
Dispose of cell debris and pathogens
Alert the adaptive immune system
Set the stage for tissue repair
What types of leukocytes are phagocytes? Natural Killer Cells?
Neutrophils are the most abundant phagocytes
Macrophages, the most voracious phagocytes, develop from monocytes
NK Cells are a type of lymphocyte, but they are “less picky” than the lymphocytes of the adaptive immune system
What type of leukocyte can differentiate into a macrophage when activated?
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Be familiar with the steps of phagocytosis. What cell organelle plays a key role?
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What does opsonization mean? Why is it a useful process?
“Opsonization”: “to make tasty” – accelerates phagocytosis
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Name 3 inflammatory mediators.
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What are phagocytes doing when they marginate?
Margination: phagocytes cling to the inner walls of capillaries and post-capillary venules to indicate the place of injury
What type of antimicrobial protein is most effective against viruses? Against bacteria?
Interferons:
Virus-infected cells secrete small proteins called interferons to help protect nearby, uninfected cells
Interferons protect neighboring cells by slowing down protein synthesis
Three types of Interferons: IFN- , IFN- and IFN-
Interferons are not virus-specific; they can be used to fight diseases like Hepatitis C and Multiple Sclerosis
Complement Proteins
A group of ~20 plasma proteins circulating in blood
An activated complement protein amplifies nearly all aspects of the inflammatory process
Activated complement proteins can lyse (kill) certain cells and bacteria
Cell lysis occurs when a group of complement proteins, called Membrane Attack Complex (MAC), forms a hole in the target cell membrane - water will influx into the cell and lyse it
What is the body’s internal thermostat? Name the substance that the body’s temperature?
Pyrogens act on the body’s thermostat and raise the body’s temperature
List two functions of a fever.
Fevers benefit the body by sequestering iron and zinc – minerals needed to support bacterial growth – and increasing the metabolic rate of tissue cells completing repair processes
