Acute Inflammation Flashcards
List the four cardinal signs of inflammation
- redness
- heat
- swelling
- pain
Inflammation delivers _____ and _____ to injured sites
nutrients and oxygen
List two functions of exudate
- carries toxins from an affected area via lymphatic drainage to local lymph nodes (where they may stimulate immune responses)
- carries antibodies and other substances into the affected area to neutralise harmful agents
Inflammation limits the spread of _____ _____ via structures such as fibrin mesh and abscess walls
harmful agents
Inflammation provides _____ to digest inflammatory exudates following the “crisis”
hydrolases
Inflammation initiates ____
repair
What three “go signals” that induce inflammation are released by tissue damage?
- Neurons - bioactive peptides
- Broken cells - intracellular molecules aka damage/danger-associated molecular patterns (DAMPs)
- Microbial products (e.g endotoxin/LPS)
What are bioactive peptides released in response to?
Pain
What do DAMPs signal and who are they sensed by?
DAMPs signal cell damage and are sensed by pattern-recognition receptors (PRRs)
What are microbial products such as endotoxin/LPS recognised as?
Pathogen-associated molecular patterns (PAMPs) by pattern-recognition receptor (PRRs)
PRRs may be _____ (complement) or ___-_____ (toll-like receptors, TLRs)
soluble or cell-bound
The cells that rapidly respond to initial “go signals” of inflammation following tissue damage are:
mast cells/basophils and macrophages
Mast cells are full of granules and initiate inflammation by releasing mediators such as: (4)
- histamine
- proteases (tryptases)
- lipid-derived signals
- cytokines (e.g TNF)
What changes do the signals released from degranulating mast cells cause? (2)
Rapid microvascular change and redness-heat-swelling-pain response
_____ is the mechanism that leads to redness and heat
vasodilation
Excess blood flow is known as:
hyperaemia
Most blood vessels are lined by ______ endothelium
continuous endothelium
Endothelial cells are closely connected by ___ junctions and ____ junctions
tight junctions and adherens junctions
Vascular permeability (leakiness) ocurs when:
Vascular permeability (leakiness) ocurs when endothelial cells retract to create gaps.
Describe venular endothelial cell reactions to mild injuries, such as an insect bite - is this reversible?
Inflammatory signals cause venular endothelial cells to rapidly and reversibly retract, creating 0.1-0.4um gaps between the cells through which protein-rich fluid (inflammatory exudate) can pass
Describe what happens to endothelial cells during severe injuries
- Endothelial cell damage
- Detachment from the basement membrane
- Persistent increases in vascular permeability
Describe the two types of persistance increases of vascular permeability during severe injury and give examples of each
- Delayed - e.g sunburn, bacterial toxins - leakage from capillaries and venules
- Immediate - e.g burns, trauma - leakage from all types of vessels until the vessel is blocked with a clot or repaired
Normally, fluid is forced out of capillaries at the _____ end via ______ pressure and re-enters them at the ___ end.
Normally, fluid is forced out of capillaries at the arteriolar end via hydrostatic pressure and re-enters them at the venular end.
During inflammation, increased hydrostatic pressure in the capillaries and increased water-binding capacity of proteins in exudates leads to _____________
Retention of fluid in the extravascular space between cells (interstitium)
Accumulated fluid generates _____, also known as _____
swelling, oedema
_____ of tissue, together with _______ mediators, causes pain
Stretching of tissue, chemical mediators
Signals that control blood vessel function during inflammation may be secreted locally by ____ or derived from ______ _______
cells, plasma proteins
Signals that control blood vessel function during inflammation induce some or all of the following actions: (5)
- Vasopermeability - generating exudate
- Vasodilation
- Neutrophil adhesion to endothelium
- Bronchoconstriction
- Pain + itching
Vasodilation occurs via synthesis of these lipid mediators (3)
- Prostacyclin I2
- Platelet-activating factor (PAF)
- Nitric oxide
What is an example of a vasoactive amine? Where can it be found?
The preformed histamine stored in granules of mast cells/basophils and platelets.
What are tryptases and what are their functions?
Tryptases are mast-cell derived serine proteases - they cleave protease-activated receptors (PARs) on other mast cells, endothelium and neutrophils, which induces inflammation
What is the membrane phospholipid phosphatidylcholine cleaved into?
lysophosphatidylcholine (LysoPC) and arachidonic acid
How are membrane phospholipids such as phosphatidylcholine cleaved?
Via intracellular Ca2+ and cytosolic phospholipase A2 (cPLA2)
LysoPC is converted into _____ in activated inflammatory cells, endothelial cells and injured tissue cells.
platelet-activating factor (PAF)
What is the function of platelet activating factor (PAF)? (2)
- Aggregation and activation of platelets
2. Leukocyte adhesion, chemotaxis and activation
What can arachidonic acid transform into? (2)
Rapid response, short half-life, short-range derivatives:
- Cyclooxygenases COX1, COX2
- 5-Lipoxygenase
What is the function of COX1 and COX2?
Generate prostaglandins, including thromboxanes and prostacyclins
What are COX1 and COX2 inhibited by?
Non-steroidal anti-inflammatory drugs (NSAIDs)
What is the function of 5-lipoxygenase?
To generate leukotrienes such as LTB4, LTD4 and LTE4
What is the function of LTB4?
Recruits neutrophils
What is the function of cysteinyl LTs such as cysLTC4, LTD4, and LTE4
Induction of vascular permeability, mucus production and bronchoconstriction
TXA2, PCI2 and PGE2 are all agents of the class ________
prostaglandin
LTB4, LTC4, LTD4 and LTE4 are all agents of the class _______
leukotriene
TXA2 activity results in:
vasoconstriction, platelet aggregation
PCI2 activity results in:
vasodilation, platelet disaggregation
PGE2 activity results in:
vasodilation, pain
prostaglandins that result in vasodilation are:
PCI2, PGE2
LTB4 activity results in:
neutrophil chemotaxis and activation