Intro to Pathophysiology Flashcards
1st Line of Defense
physical, mechanical and biochemical barriers
- skin and low temperature
- linings of the GI, genitourinary and respiratory tracts
Two Biochemical Barriers
- Epithelial-Derived Chemicals
- antimicrobial peptides (AMPs): cathelicidins, defensins and collectins - Bacteria-Derived Chemicals
- normal bacterial flora
- inhibit colonization by pathogens
2nd Line of Defense
inflammatory response
- non-specific
- intensity depends on the extent/severity of the injury and reactive capacity of the patient
- vascular and cellular response
What causes 2nd Line of Defense?
Infection Mechanical damage Ischemia Nutrient deprivation Temperature extremes Radiation
What is the goal of the inflammatory response?
a. neutralizes/dilutes the inflammatory agent
b. remove necrotic material
c. establish an environment for healing
Manifestations of Inflammation
a. erythema - hyperemia from vasodilation
b. heat - increased metabolism
c. pain - changes in pH, nerve stimulation by chemical mediators, fluid change
d. swelling - fluid shift, accumulation of exudate
e. loss of function - due to swelling and pain
Vascular Response
Transient Vasoconstriction
- lasts only a few seconds
»
Fibrin clot, release of chemical mediators
- seal off injured area, control inflammatory process
»
Local vasodilation and hyperemia
- increase permeability, facilitate movement of WBC, fluids and nutrients
Cellular Response
Chemotaxis, margination and diapedesis of blood leukocytes >> Migration of leukocytes to the site of injury >> Neutrophils - 6-12 hours, forming pus when it dies Monocytes >> Macrophages - 3-7 days >> Phagocytosis
Chemotaxis
movement of a cell or organism in response to chemical stimulus, along gradient of concentration
Margination
leukocytes get close to the vessel
Diapedesis
leukocytes enter into the vessel
Types of Leukocytes
Neutrophils: phagocytosis of foreign material
Monocytes: mature into macrophages
Eosinophils: kill parasites
Basophils: secrete chemical mediators
(Nice Monkeys Eat Bananas)
What is the order of leukocytes from greatest to least in quantity?
Neutrophils Lymphocytes Monocytes Eosinophils Basophils
(Nobody Likes My Emotional Breakdown)
What is a chemical mediator?
Any messenger that acts on blood vessels, inflammatory cells or other cells to contribute to any inflammatory response
Histamine
chemical mediator stored in granules of basophils, mast cells, platelets
What is the mechanism of action of histamine?
causes vasodilation and increased vascular permeability
Kinins
i.e. bradykinin
chemical mediators that arise from polypeptides that circulate in the blood in inactive form (Kininogens)
What is the mechanism of action of Kinins?
cause contraction of smooth muscle and dilation of blood vessels»_space; pain
Complement component
C3a, C4a, C5a
anaphylatoxic agents generated from complement pathway activation