Acute & Chronic Inflammation and Hypersensitivity Flashcards
What are Toll-like receptors?
TLRs are surface receptors that respond to patterns on extracellular microbes. Activation leads to release of TNF.
What are inflammasomes
Inflammasomes are intracellular receptors that detect fragments of dead cells and some microbes. Activation of the inflammasome leads to activation of caspase-1, which in turn activates release of IL-1.
Vasodilation is mediated by what?
Histamine and nitric oxide (NO)
Vascular permeability is mediated by what?
histamine and bradykinin
Histamine: what is it released by and what does it mediate?
Released by: mast cells (stimulated by IL-1 and other inflammatory cytokines) Produces vasodilation and increases vascular permeability
Nitric oxide: what is it released by and what does it mediate?
Released by: endothelial cells in response to injury Increases vasodilation
Bradykinin: what is it released by and what does it mediate?
Bradykinin is a plasma protein produced by the liver. It is activated by factors expressed on injured epithelial cells. Bradykinin increases vasodilation, increases vascular permeability, and causes pain
Define edema
excess fluid in the interstitium
Compare/contrast: Trasudate vs. Exudate
Transudate: SG < 1.012, protein-poor ultrafiltrate of blood plasma due to increased hydrostatic pressure or lowered plasma osmotic pressure. Non-inflammatory. Exudate: SG > 1.02, protein and inflammatory cell rich fluid released due to increased vascular permeability. Due to inflammatory process.
What is pus?
Purulent exudate -> exudate rich in neutrophils (PMNs)
List the major steps in leukocyte recruitment
- margination
- rolling
- adhesion
- transmigration
- chemotaxis
Name the receptor associated with each of the following steps of leukocyte recruitment:
- rolling
- adhesion
- transmigration
- selectins
- ICAM-1
- PECAM-1 (CD31)
Selectins are expressed on endothelial cells in response to what?
Histamine, thrombin, etc
ICAM-1 is expressed on endothelial cells in response to what?
TNF and IL-1 secreted by macrophages at the site of injury
What is diapedesis?
Movement of a leukocyte through the epi/endothelial barrier
Killing and degradation of microbes/tissues at the site of injury is driven by what two processes?
- ROS (within phagolysosome)
- Enzyme release (example: elastase, extracellular)
Name the principal mediators of the following features of inflammation:
- Vasodilation
- Increased vascular permeability
- Chemotaxis and leukocyte recruitment
- Fever
- Pain
- Tissue damage
- histamine and nitric oxide
- histamine and bradykinin
- TNF, IL-1, bacterial products
- TNF, IL-1
- bradykinin
- ROS, NO, lysosomal enzymes
Name four major morphologies of acute inflammation
- serous
- fibrinous
- suppurative
- ulcerative
Describe serous acute inflammation
- mildest form of acute inflammation
- consists mostly of transudate from injured serious tissues
- example: pleural/pericardial/peritoneal effusion due to chronic heart failure or fluid overload
- example: skin blistering from friction, burn, trauma, or viral infection due to leaky epi/endothelia
Describe fibrinous acute inflammation
- usually secondary to a more severe injury
- larger vascular leaks, allowing passage of fibrinogen and conversion to fibrin
- examples: fibrous pericarditis, fibrous peritonitis with ascites, acute rheumatoid fever (ARF)
Describe suppurative acute inflammation
- suppurative = purulent (pus)
- S. aureus is common
- formation of an abscess: central necrotic tissue with PMNs enclosed by fibroblasts
- examples: acute appendicitis, acute bronchopneumonia, acute meningitis
Describe ulcerative acute inflammation
- local defect on surface of organ or tissue
- sloughing of surface and necrotic tissue
- examples: peptic ulcer, skin ulceration (common with diabetes)
A friction rub on cardiac auscultation may be indiciative of what type of inflammation?
Fibrinous inflammation
Acute appendicities is usually an example of what type of acute inflammation?
suppurative inflammation
Tissue macrophages are a hallmark sign of what type of inflammation?
Chronic inflammation
What is polymyositis?
Chronic inflammation (autoimmune) characterized by CTL destruction of skeletal myofibers
What type of inflammation is defined by the presence of epithelioid macrophages?
Granulomatous inflammation
example: sarcoidosis is defined by the presence of granulomatous inflammation