Inflammation Flashcards
What are the 5 main signs on inflammation?
Redness, heat, swelling, pain and loss of function.
What are the steps for inflammation?
Change in local blood flow, structural changes in microvascalature, recruitment of immune cells and proteins.
2 examples of inflammatory signals when a wound occurs?
Non apoptotic cell death and foreign material.
After damage to tissue occurs and inflammatory signals are released, what happens?
Vasodilators are released - histamines and nitric oxide.
What do vasodilators result in?
Vascular changes. Increased permeability. Dilation. Plasma leakage.
How does increased vascular permeability and leakage act as a barrier to pathogens?
Increased swelling. Pathogens have to travel further.
Apart from histamines what other molecules are found at injury?
Prostaglandins, cytokines, chemokines and complement proteins.
What is exudate?
Fluid, proteins and cells that have seeped out of a blood vessel.
When it comes to immune cell recruitment what do chemokines do?
Chemokines diffuse out to form a gradient. Leukocytes expressing complementary chemokine receptors migrate towards chemokine source.
What is neutrophil extravasation?
Neutrophil extravasation is the movement of neutrophils out of the circulatory system and towards the site of tissue damage or infection.
What is the first step of neutrophil extravasation?
Leukocyte such as a macrophage releases cytokines that activate adhesion molecules (selectins) on endothelial surface.
What is the second step of neutrophil extravasation?
Integrins in low affinity state on neutrophils bind to selectins. This is referred to as rolling adhesion.
What is the third step of neutrophil extravasation?
Chemokines promote low to high affinity switch integrin switch.
What is the fourth step of neutrophil extravasation?
Cytoskeletal rearrangement to migrate out of endothelium.
How do neutrophils recognise gram negative bacteria?
Use their receptors to recognise lipopolysaccharide molecules on surface of gram negative bacteria.
How do neutrophils directly clear pathogens?
Phagocytosis. Netosis.
How do neutrophils indirectly clear pathogens?
Release cytokines which recruits and activates other immune system cells.
Explain phagocytosis process
Microbe engulfed into phagosome. Phagosome fuses with lysosome to form phagolysosome. Reactive oxygen species and antimicrobial peptides kill microbe in phagolysosome.
What do macrophages do to resolve inflammation?
Clear apoptotic cells. Produce anti inflammatory mediators.
What can cause chronic inflammation?
Autoimmunity, prolonged infection, persistent toxic stimuli and unclearable particulates.
What cells do you see in chronic inflammation?
Lymphocytes, macrophages, and plasma cells
What repair processes occur in chronic inflammation?
Angiogenesis and fibrosis.
What is the main cell in acute inflammation?
Neutrophils.
What can happen when monocytes are recruited to tissue from blood?
They can differentiate into macrophages.
Key macrophage features?
Phagocytic, cytotoxic, anti-inflammatory and involved in wound repair.
What is granulomatous inflammation?
Chronic inflammation with formation of granulomas.
Why are granulomas formed?
To act as a barrier. To contain an area of bacterial, viral or fungal infection so it can try to keep it from spreading.
What causes granulomatous inflammation to form?
Strong T cell response.
Characteristics of chronic inflammation?
Persistent inflammation, monocytes and macrophages are the dominant cell type present, ongoing cytokine release and scarring. T cells and B cells also present.
Characteristics of acute inflammation?
Vasodilation, increased vascular permeability, neutrophils dominant cell type present, histamine release and necrosis.
Consequences of long term inflammation?
Tissue damage, scarring, loss of function which can lead to organ failure.
Explain what leads to swelling in inflammation?
Vascular leakage increases blood flow into the inflamed tissue, leading to fluid build-up.
Explain what leads to redness in inflammation?
Accumulation of blood contents including red blood cells near surface of skin.
Explain what leads to heat in inflammation?
Heat results from the increased presence of fluid at core body temperature at a site that would otherwise have a limited exposure to this. During inflammation infiltrating immune cells are also highly metabolically active, which may also contribute to the generation of heat as a by-product.
Explain what leads to pain in inflammation?
Inflammatory mediators signalling on local nerve cells.
