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.