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26 Cards in this Set

  • Front
  • Back
What are the four main physical barriers?
GI Tract
What is skin composed of?
epidermis (keratin)
Why is the skin a good barrier (4 reasons)?
low moisture

high salt

sebaceous glands secrete fatty and lactic acids which decrease pH

antimicrobial peptides expressed in sweat glands (ie Dermcidin)
How many bacteria is URT exposed to in a typical day?
What are the major barriers within the URT?
mucocilliary system
antimicrobial peptides in body secretions
normal flora
What is the function of mucous? Of cilia?
mucous traps, cilia sweeps
Give an example of an opportunistic pathogen in URT
Neisseria meningitidis
What is the URT?
The nose, throat, and ears
What is the LRT?
trachea, bronchial tubes, alveoli in lungs
What are the three LRT defence mechanisms?
mucocilliary system
macrophages and antibodies in lungs
antimicrobial proteins and peptides
What antimicrobial peptides are present in LRT? Proteins?
Peptides: defensins, LL-37
Proteins: lactoferrin, lysozyme
What part of the body contains the majority of normal flora?
GI tract
What are the three GI tract defenses?
stomach acidity
peristaltic movements (expels potential colonizers)
microbial antagonism from normal flora
What are the main antimicrobial substances?
antimicrobial peptides (beta-defensins, LL-37)
What does lactoferrin?
binds iron
What do enzymes such as lacteroperoxidase do?
generate singlet oxygen to kill bacteria
Where are antimicrobials found?
tears, saliva, lymph, mucus, blood
How does inflammation help against bacterial infections?
limits spread
recruits phagocytes
enhances phagocytosis
repairs tissue damage
___ bind to ___ in blood and ___ cells in tissue resulting in histamine release
mast cells
What does the release of histamine cause?
What is the function of fibrinogen in acute inflammation?
forms a fibrin clot around damages host cells localizing the infection
What process is responsible for fever in chronic inflammation?
production of cytokines
How do activated/inflammatory macrophages damage tissue?
secrete toxic oxygen intermediates, and tissue-damaging enzymes
Why is chronic inflammation bad?
extensive tissue damage, fever
What bacteria causes the chronic infections: gastritis, gastric ulcers, and gastric cancers?
Helicobacter pylori
How are peptic ulcers perpetuated?
Bacteria lives in mucous layer lining, secreteing urease to nutralize stomach acid and protect itself. Chronic inflammation destroys stomach lining, which allows HCl access to deeper tissues.