Acute inflammation Flashcards

(32 cards)

1
Q

What is acute inflammation?

A
  • Initial response to tissue injury
  • Relatively non-specific
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are triggers of acute inflammation?

A
  • Pathogens/infection: bacteria, viruses, parasites
  • Physical: frost bites, burns, radiation
  • Chemical: chemical burns, irritants
  • Mechanical: trauma, tissue crush
  • Foreign: silica, swallowed bones, dentures, sutures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the purpose of acute inflammation?

A
  • Alert the body
  • Limit spread (of infection/injury)
  • Protect injured site from becoming infected
  • Eliminate dead cells + tissue
  • Create conditions required for healing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the signs of inflammation?

A
  • Redness (rubor): inc BF to injured area
  • Swelling (tumor): fluid accumulation due to inc vasc perm
  • Heat (calor): inc BF + metabolic activity
  • Pain (dolor): release of pain mediators; inc pressure on nerve ends
  • Loss of function (functio laesa): xs swelling + pain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What agents cause fever?

A

Pyrogens: IL-1, TNF-a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What causes neutrophilia?

A
  • G-CSF stimulation of bone marrow
  • Replenish dead neutrophils
  • Release of immature neutrophils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the acute phase reactants?

A
  • CRP, fibrinogen, complement, SAP
  • prod in liver
  • induced by IL-6, IL-1, TNF-a
  • Inc fibrinogen -> roleaux -> higher ESR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 4 vascular events of acute inflammation?

A
  1. Vasodilation: due to histamine, 5HT release from injured cells
  2. Inc BF to injured area: results in influx of WBC, O2, nutrients
  3. Inc vessel perm: endothelial cells contract, results in leakage of fluid + cells in injured tissue
  4. Walling off of injured area: due to formation of fibrinogen clots
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does inflammatory exudate consist of?

A
  • Water
  • Salts
  • Small plasma proteins (fibrinogen)
  • Inflammatory cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 different types of inflammatory exudate?

A
  • Purulent
  • Fibrinous
  • Serous
  • Haemorrhagic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the cellular events of acute inflammation?

A
  1. Migration + accumulation of cells
    - > first step - neutrophils
    - > involves a complex process of exit from blood vessels
  2. Removal of pathogens/injured/dead cells
    - > neutrophils phagocytose pathogens + dead tissue
    - > neutrophils live briefly -> dead neutrophils = pus
  3. Migration + accumulation of monocytes
    - > monocytes diferentiate into macrophages
    - > phagocytosis -> clearance of injured site
    - > release factors that promote tissue repair (TGF-B)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

RIFTC

What are the 5 steps of neutrophil recruitment?

A
  1. Rolling
  2. Integrin activation by chemokines
  3. Firm adhesion
  4. Transmigration through endothelium into tissue
  5. Chemotaxis to inflammed site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which molecules are involved in neutrophil recruitment?

A
  • Selectins
  • Integrins
  • Immunoglobulin superfamily cell adhesion molecules (CAMs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the role of selectins?

A
  • Mediate rolling of neutrophils
  • Expressed by activated endothelium
  • Selectins bind to ligands on neutrophils
  • Ligands - carbohydrates
  • Low affinity interaction -> disrupted by flowing blood -> repetetive binding + detaching -> rolling; slow down
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the two types of selectins?

A
  • P-selectin - preformed granules
  • E-selectin - induced by IL-1 and TNF-a
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does integrin play into neutrophil recruitment?

A
  • Rolling neutrophils express integrins (LFA-1)
  • Integrins in low affinity configuration; no binding to ligands
  • Activated endothelial cells produce chemokines
  • Chemokines bind to receptors on neutrophils
  • -> integrin activation -> high affinity configuration
  • Binding of integrins to ligands on endothelium
  • -> firm adhesion of neutrophils to endothelium
  • Integrin ligands: ICAM-1, VCAM-1
17
Q

Describe neutrophil transmigration

A
  • Neutrophils migrate through interendothelial spaces
  • Neutrophils pass through vessel wall + enter tissue
  • Migrate (chemotaxis) through tissue towards inflammed site
18
Q

Describe neutrophil chemotaxis including examples

A
  • Movement of cells into inflammed sites
  • Guided by chemoattratants:
    • Chemokines (IL-8)
    • Complement components (C5a)
    • Bacterial components (formyl-methionyl petides)

*Note that monocytes use similar mechanisms to leave blood vessels and enter sites of inflammation

19
Q

At the inflammation site, neutrophils clear pathogens. How do they do this?

A
  • Release of granule content
  • Phagocytosis
  • Generation of reactive oxygen species
  • Formation of Neutrophil Extracellular Traps (NETs)
20
Q

What can be phagocytosed?

A
  • Pathogens
  • Damaged cells
  • Dead cells
  • Nutrients
21
Q

What are the roles of phagocytosis?

A
  • Protection from pathogens
  • Disposal of damaged/dying cells
  • Processing + presentation of antigens
    • activation of adaptive immune system
    • links innate + adaptive immunity
22
Q

Name some mediators of acute inflammation

A
  • Inflammatory cytokines: IL-1, TNF-a
  • Histamine, prostaglandins, leukotrienes
  • Chemokines: IL-8
  • Complement (C5a)
23
Q

What are the 3 possible outcomes of acute inflammation?

A
  1. Resolution
  2. Repair
  3. Chronic inflammation
24
Q

What is regeneration?

A
  • Damaging agent removed
  • Injured tissue replaced by cells of same type
  • No change in tissue structure/function
25
What is repair by replacement?
* Injured tissue replaced with connective tissue * Scarring -\> can alter tissue function
26
What is an abscess?
* Mass of necrotic (dead) tissue * Caused by pyogenic (pus-forming) bacteria * Can become chronic if not reabsorbed/drained
27
Which tissues have **high** regeneration ability?
* Epithelial cells * Blood cells Sometimes perfect regeneration, no scarring
28
Which tissues have an **intermediate** regeneration ability?
* May regenerate when injured * Eg. liver, kidney, pancreas * If extensive injury -\> scarring
29
Which tissues have no/limited regeneration ability?
* Neurons * Skeletal muscle * Myocardium Heal with fibrosis, scarring, loss of function
30
What are factors that favour resolution?
* **minimal** destruction * minimal cell death * **good regenration** **ability** of injured tissue * **fast clearance** of infection * **quick removal** of dead tissue (debris)
31
What factors prevent healing?
* **extensive** injury * poor **vascular supply** * haemorrhage * infection * poor **general health**/nutrition; diabetes * old age * drugs: corticosteroids
32
What is chronic inflammation?
* damaging/infective agent persists * persistent inflammation * tissue destruction