Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
26 Cards in this Set
- Front
- Back
|
What are the four main physical barriers?
|
Skin
URT LRT 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?
|
>1000
|
|
|
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?
|
lysozyme
lactoferrin lactoperoxidase 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
|
anaphylatoxins
basophils mast cells |
|
|
What does the release of histamine cause?
|
vasodilation
|
|
|
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.
|
