Week 3- Inflammation Flashcards
What is inflammation?
A non specific response to injury designed to remove the cause and consequence
What are the 4 signs of acute inflammation? (Give the english AND latin)
Color/rubor
Pain/dolor
Swelling/tumor
Heat/calor
What are some causes of acute inflammation?
Allergens, non apoptotic cell injury, physical damage, temperature
What are the 3 steps of acute inflammation? Briefly describe each one
- Steady state
- Damage: inflammatory signals, vasodialators eg histamine released, vascular changes eg increased permeability, plasma leakage, reduced flow, dilatation
- Immune cell recruitment: chemokines produced at injury site and diffuse out in a gradient, leukocytes w complementary receptors migrate to chemokine source
What is exudate?
When fluid, proteins and cells leak out of blood vessels
What are some soluble mediators that may be released at the site of injury?
Histamine, chemokines, cytokines, complements
Describe the process of neutrophil extravasion
- Cytokines cause endothelial upregulation of adhesion molecules called selectin
- Carbohydrate ligands on neutrophils bind to selectins
- Chemokines encourage tight adhesion by stimulating a low to high affinity switch
- Transmigration occurs where the cytoskeleton is rearranged to allow the neutrophil to enter the cell without cell death
What do neutrophils do once they have reached the sight of inflammation?
- Pathogen recognition (via polysaccarides)
- Pathogen destruction (via phagocytosis or netosis where the neutrophil releases its DNA and traps the pathogen in a DNA net)
- Cytokine secretion (more immune cells are recruited)
What is netosis?
When at the sight of inflammation, the neutrophil releases its DNA and traps the pathogen in a DNA net
How is acute inflammation resolved?
- Neutrophils have a short half life
- Macrophages clear apoptotic cells and produce anti inflammatory mediators
- ECM is deposited at the site for repair
What is chronic inflammation?
Chronic inflammation is persistent/ongoing due to constant stimuli
Macrophages, T cells etc are recruited instead of neutrophils
The agent is not cleared
How are macrophages involved in inflammation?
Recruited as monocytes
Tissue resident
Phagocytic, cytotoxic, anti inflammatory
Cons: can be pro fibrotic, cytotoxicity kills good cells
How are lymphocytes involved in inflammation?
Innate and adaptive cells work together, T cells (cytotoxic, regulatory) and B cells (produce antibodies and can operate remotely or locally)
What is granulomatous inflammation?
Chronic inflammation w formation of granules (these are accumulations of activated macrophages)
Triggered by strong T cell responses
Describe the differences between acute and chronic inflammation in terms of: onset, molecules that dominate, molecules that are released and what happens after
Onset: immediate vs delayed
Molecules that dominate: neutrophils vs monocytes
Molecules that are released: histamine vs cytokines
Aftermath: necrosis vs scarring
