Additional Flashcards for final
What is the nonspecific resistance first line of defense?
- intact skin
- mucous membranes and secretions
- normal microbiota
What is the nonspecific resistance second line of defense?
- Phagocytic white blood cells
- inflammation
- fever
- Antimicrobial substances
What is Phagocytosis?
(Phago: eat, Cyte: cell) The ingestion of microbes or particles by a cell, performed by phagocytes.
What are the two types of white blood cells?
Granulocytes
Agranulocytes
What are the three types of granulocytes? what does each deal with?
- Neturophils - bacterial infection and other very small inflammatory processes; forms pus
- Basophils - allergic and antigen response by releasing the chemical histamine causing inflammation
- Eosinophils - parasitic infections
leukocyte
White blood cell
What are the three types of agranulocytes?
- lymphocytes
- monocytes
- macrophages
What do monocytes do?
perform phagocytosis - present pieces of pathogens to T cells so that the pathogens may be recognized again and killed (live long)
What are the three types of lymphocytes? What does each do?
- B cells - make antibodies that bind to pathogens to enable their destruction
- T cells - coordinate the immune response and are important in the defence against intracellular bacteria
- Natural killer cells - kill cells of the body which are displaying a signal to kill them, as they have been infected by a virus or have become cancerous
Explain the 7 steps of phagocytosis.
- Chemotaxis and adherence of microbe to phagocyte
- Ingestion of microbe by phagocyte through the plasma membrane and into the cytoplasm
- Formation of phagosome
- Fusion of the phagosome with a lysosome to form a phagolysosome
- Digestion of ingested microbe by enzymes.
- Formation of residual body containing indigestible material.
- Discharge of waste materials out of the cell (phagocyte).
What are some examples of microbial evasion of phagocytosis (6)?
- Inhibit adherence (M protein, capsules) - Streptococcus pyogenes and S. pneumoniae
- Kill phagocytes (leukocidins) - Staphylococcus aureus
- Lyse phagocytes (membrane attack complex) - Listeriamonocytogenes
- Escape phagosome - Shigella
- Prevent phagosome (lysosome fusion) - HIV
- Survive in phagolysosome - Coxiella burnetti
What are some symptoms of inflammation?
Redness Pain Heat Swelling Vasodilation
What are some chemicals released by damaged cells and what does each do?
Histamine - vasodilation, increased permeability of blood vessels
Kinins - vasodilation, increased permeability of blood vessels
Prostaglandins - intensify histamine and kinin effect
Leukotrienes - increased permeability of blood vessels, phagocytic attachment
What does the hypothalamus normally set our body temperature at? What happens when we get a fever?
Temp normally set at 37 degrees celsius.
- Gram-negative endotoxin cause phagocytes to release interleukin 1.
- Hypothalamus releases prostaglandins that reset the hypothalamus to a high temperature
- Body increases rate of metabolism and shivering to raise temperature
- When interleukin 1 is eliminated, body temperature falls. (crisis)
What is the complement system?
a biochemical cascade of the immune system that helps clear pathogens from an organism which promotes healing.
What is the complement system derived from and what do they do?
It is derived from many small plasma proteins that work together to form the primary end result of cytolysis by disrupting the target cell’s plasma membrane.
What do the actions of the complement system affect?
both innate immunity and acquired immunity.
What does activation of the complement system lead to?
cytolysis chemotaxis opsonization immune clearance inflammation the marking of pathogens for phagocytosis
What does the complement system consist of?
more than 35 soluble and cell-bound proteins, 12 of which are directly involved in the complement pathways. The proteins account for 5% of the serum globulin fraction. Most of these proteins circulate as zymogens, which are inactive until proteolytic cleavage. The complement proteins are synthesized mainly by hepatocytes; however, significant amounts are also produced by monocytes, macrophages, and eptihelial cells in the gastrointestinal and genitourinary tracts.
What is the immune system?
the body’s system of defenses against disease, composed of certain white blood cells and antibodies.
Antibody (Ab)
protein substances that react against bacteria and other harmful material.
What is the most abundant of the white blood cells?
Neturophils
What is the least abundant of the white blood cells?
Basophils
Immunity
specific antibody and lymphocyte response to an antigen
Antigen (Ag)
substance that causes the body to produce specific antibodies or sensitized T cells
Serology
study of reactions between antibodies and antigens
Antiserum
generic term for serum because it contains Ab
Globulins
serum proteins
Gamma globulins
serum fraction containing Ab
Acquired immunity
developed during an individuals lifetime
humoral immunity
involves Ab produced by B cells
cell-mediated immunity
involves T cells
What is the adaptive immune system based on?
dedicated immune cells termed leukocytes that are produced by stem cells in the bone marrow, and mature in the thymus and/or lymph nodes
How does innate immunity differ from adaptive immunity?
it does not recognize every possible antigen. Instead, it is designed to recognize molecules shared by groups of related microbes that are essential for the survival of those organisms and are not found associated with mammalian cells
How does one acquire immunity?
- naturally acquired active immunity - resulting from infection
- naturally acquired passive immunity - transplacental or via colostrum
- Artificially acquired active immunity - Injection of Ag (vaccination)
- Artificially acquired passive immunity - injection of Ab
What do antibodies react with?
Antigenic determinants
Hapten
a small molecule which can elicit an immune response only when attached to a large carrier such as a protein
How do you go about isolating and identifying an unknown microbe?
- Quadrant Streak (colony morphology): Shape, margin, elevation, texture, pigment, surface
- Stain: cell morphology and arrangement
- Gram Stain: tells about cell wall architecture (differential stain)
- Acid Fast Stain: (differential stain)
- Selective Media/Biochemical tests
- PCR
