Intro to Inflammation and Infection Flashcards
describe the 4 purposes of inflammation
- to destroy the pathogen or noxious stimulant
- to destroy infected cells
- to expel noxious or foreign material and remove cellular debris
- to help aid in the healing of tissues
list the 3 types of stimuli that can initiate and inflammatory response and recognize examples of each
- microbes: PAMPs like peptidoglycan, LPS, dsRNA
- injured cells of the body: DAMPs can be intracellular (like when cells rupture) or extracellular
- foreign material
describe the role of PRRs in inflammatory responses
bind their respective PAMP, initiate a signaling cascade, activate transcription factors, and lead to expression of genes like pro-inflammatory cytokines, chemokines, adhesion molecules, and co-stimulatory molecules
list basic categories of inflammatory mediators; briefly describe their targets and effects at the tissue or cellular level
cellular:
1. released by macrophages: pro-inflam cytokines, chemokines, and eicosanoids
2. released by mast cells: histamine
3. released by other cells: chemokines and cytokines
4. released by cell membranes: lipid mediators, arachadonic acid
plasma:
complement, kinins, plasmin, clotting cascade
effects/steps of extravasation:
1. vasoactive mediators cause vasodilation, which slows down blood flow, making it easier for inflammatory cells to exit vessels
2. vascular permeability increases: endothelial walls of small vessel walls are less tightly bound to each other, making it easier for inflammatory cells to get to the tissue
3. neutrophils migrate to site of infection via diapedesis/extravasation
describe the 5 cardinal signs of inflammation
- redness: due to vasodilation
- heat: due to vasodilation
- swelling: due to vasodilation, increased vascular permeability, and immune cell influx
- pain: due to nocioceptor stimulation (physical and chemical) and immune cell influx
- loss of function: due to physical disruption of tissues, immune cell influx, and remodeling of tissues over time
describe the blood vessel changes that occur during inflammation
- small blood vessels dilate
- vascular permeability increases
- neutrophils migrate to site of infection
describe the basic steps of extravasation and chemotaxis of leukocytes
- rolling
- adhesion to endothelial cells
- crawling, firm adhesion, and patrolling
- transendothelial migration (extravasation): after approaching the site of inflammation, neutrophils find a small gap between pericytes, migrating through the space by forming a protuding uropod that allows neutrophils to access the inflamed area
- leukocytes follow a chemical gradient to reach the site of inflammation in tissues