Physiology of Inflammation Flashcards
5 cardinal signs of inflammation
- calor (heat)
- rubor (redness)
- tumor (swelling)
- dolor (pain)
- functio laesa (loss of function)
3 phases of inflammation
1) Initiation
- stimulus occurrence and its recognition
- local production of inflammation mediators
2) Patent inflammation processes
- local dilation of capillaries increase blood flow
- micro vascular structural changes and escape plasma proteins from the blood stream
3) Resolution
- removal of stimulus
- inhibitory feedbacks and counter- balanced cellular and humoral responses
- repair, wound healing, if adaptive- memory development
Causes of inflammation
- infections or microbial specific exotoxins, endotoxins and pathological mechanisms
- tissue injury/ death
- hypersensitivity
Examples of inflammatory diseases
- Gout
- IBS
- rheumatoid arthritis
- autoimmune diseases
Morphological patterns of inflammation
- Serous
- fibrinous
- haemorrhagic
- suppurative
- necrotising
- ulcers
2 classifications of inflammation
- Acute
- Chronic
Features of acute inflammation
- fast onset
- prominent signs
- mild outcomes
- self limited
Features of chronic inflammation
- slow onset
- less prominent signs
- severe outcomes
- progressive disease
Examples of acute phase proteins
- ↑ CRP
- Fibrinogen
- Haptoglobin
What happens in stimulus occurrence?
Infection
- virus
- bacteria
- fungi
- eukaryotic parasites
What happens in stimulus recognition?
Humoral factors
- complement system
- antibodies
- other proteins
Innate cell recognition
- PRRs (Toll-like receptors)
- complement and antibody responses
Adaptive immuno-recognition
- specific responses
What does PAMPS stand for?
Pathogen associated molecular patterns
What does DAMPs stand for?
Damage associated molecular patterns
What does SAMPS stand for?
Self/suppression associated molecular patterns
Feature of the initial local mediator release
Autocrine and paracrine cellular responses:
- mediated by diverse cell types and vast ranger of different receptors
- release of other mediators by surrounding cells, local and systemic responses
Mediators of inflammation and examples
- Amines (histamine)
- Lipids (prostaglandins, Leukotrienes
platelet-activating factor) - Peptides (bradykinin)
- Proteins (cytokines)
- Chemokines
- Enzymes
How does vasodilation occur?
Mainly due to histamine and NO
- released by mast cells and macrophages
- also promoted by PAF, bradykinin PGE1 and 2
What causes swelling?
- micro vascular leakage occurs in post capillary venules
- mainly due to histamine
endothelial cells retraction and rearrangement of tights-junctions forming gaps between them and allows fluid exudation - loss of protein leads to oedema
Where is histamine released from?
What do histamines do? (2)
- Mast Cells
- dilate blood vessels
- ↑ micro vascular permeability
What is the function of Histamine H1 receptors?
G protein couple receptor
- ↑ Ca2+
- smooth muscle contraction
- ↑ capillary permeability
- vasodilation
- sensory nerve endings pain and itching
IMPORTANT- for asthma and allergies
Lipids as mediators of inflammation (4)
1) stored in phospholipid molecule
2) enzyme phospholipase A2 breaks down phospholipids
3) IFN-y, IFN-a, b-FGF receptor - phosphorylation and CA2+ influx
4) Phospholipid broken down into Arachidonic acid and Lyso-glyceryl-phosphorylcholine (Platelet activating factor)
How is platelet activating factor produced?
Produced mainly by platelets, mast cells, neutrophils, macrophages, endothelial cells:
1. Phospholipids
2. Lyso-glyceryl-phosphorycholine
3. Platelet activating factor
4. PAF-receptors
What does platelet activating factor do? (8)
- Strong vasodilation
- ↑ vascular permeability
- bronchoconstriction
- platelet aggregation and degranulation
- leukocyte chemotaxis, extravasation
- promote neutrophil oxidative burst
- ↑ production of eicosanoids by inducing Cox2 transcription
- ↑ transcription of IL-6, MMPs and iNOS
Eicosanoids precursors
Arachidonic acid (20 carbon lipid)
EPA = Eicosapentaenoic acid (omega-3 fatty acid)
DHA = Docosahexaenoic acid ( 22 carbon omega 3 fatty acid)