Pathology - Inflammation and Repair Review Flashcards
what is inflammation?
a response from vascularised tissue to injury
4 purposes of inflammation
- deliver necessary components to site
- isolate injury
- destroy microbes
- remove debris
2 types of inflammation
acute
chronic
what is the dominant cell in acute inflammation?
neutrophil
what is the dominant cell in chronic inflammation
lymphocytes/macrophages
describe acute inflammation - onset, duration
early onset
short duration
describe chronic inflammation - onset, duration
later onset
longer duration
5 signs of inflammation
calor - heat
dolor - pain
rubor - redness
tumour - swelling
function laesa - loss of function
what are the 5 R’s?
recognition
recruitment
removal
regulation
repair
define acute inflammation
rapid host response that delivers:
- leukocytes
- plasma proteins - antibodies and fibrinogen
to sites of infection or tissue injury
what changes occur in acute inflammation?
vascular and cellular reactions:
- increased vasodilation
- increased vascular permeability
- recruitment of leukocytes
what does increased vasodilation and vascular permeability lead to?
oedema
- protein rich exudate releases into the extravascular tissues
what affect does oedema have on the blood flow?
the blood flow decreases and the viscosity increases as the concentration of RBC increase
what does slower blood flow lead to?
stasis
what are the 5 step cellular changes in acute inflammation?
- margination
- rolling
- adhesion
- migration
- chemotaxis
describe margination (2)
vascular stasis
neutrophils move out from central axis toward vessel wall
describe rolling.
- cytokines activate endothelial selectins
- neutrophil surface ligand interact with the selectins
- roll along the surface
what is a selectin?
self-adhesion molecule
describe adhesion.
- change in integrin
= higher affinity binding site to selectins - neutrophil stops rolling
describe migration.
neutrophil moves across blood vessel wall via PECAM-1
describe chemotaxis
neutrophils exit
move to site of injury via chemokine gradient
what are 2 types of chemokine? give examples.
exogenous - bacterial products
endogenous - cytokines, complement, arachidonic acid metabolites
3 Roles of a Neutrophil
phagocytosis
engulfment
killing/degradation
6 Benefits of acute inflammation
- dilute toxins
- antibodies
- drug delivery
- nutrient and oxygen delivery
- fibrin formaiton
- stimulates immune response
3 Harmful Effects of Acute Inflammation
- lysosomal enzymes can digest normal tissue
- swelling
- may be inappropriate response
4 ways in which acute inflammation may appear as a morphological pattern
SEROUS INFLAMMATION
FIBRINOUS INFLAMMATION
PURULENT/SUPPURATIVE INFLAMMATION
ULCERATION
How does Serous Inflammation Appear Morphologically?
- exudation of cell-depleted fluid into body cavity
- few microbes and cells
How does Fibrous Inflammation Appear Morphologically?
formation of fibrin
How does Purulent Inflammation Appear Morphologically?
- infection + neutrophils
- lead to necrosis
- lead to pus
How does Ulceration Appear Morphologically?
- loss of surface integrity due to shedding of necrotic tissue
what is an abscess?
a localised collection of pus
what is pus-producing bacteria called?
pyogenic
what happens if acute inflammation persists, non-resolving or may be too prolonged?
chronic inflammation
what inflammation is atheroscelerosis? how is it induced?
chronic
induced by tissue deposition of lipids/cholestrol
4 Features of chronic inflammation
- mononuclear cell infiltration
- macrophages
- tissue destruction
- healing
How does Healing Appear?
blood vessel proliferation - angiogenesis
granulation tissue
Roles of a Macrophage
phagocytic
initiate tissue repair - scar or fibrosis
secrete inflammatory mediators
interact with lymphocytes - present antigen
What Is Granulomatous Inflammation?
a distinctive pattern of chronic inflam
the bodies response to try contain agents which are difficult to eradicate
Name 7 Conditions which can Lead to Granulomatous Tissue.
tuberculosis
leprosy
syphilis
cat-scratch disease
sarcoidosis
Crohn disease
industrial dust exposure
How do granulomas appear microscopically?
- aggregation of macrophages
- collar of mononuclear leukocytes
- giant cells
what are the 2 types of giant cells and how do they present?
peripheral nuclei - look like horse shoe
= langerhans giant cell
- very common with tuberculosis
haphazard nuclei
= foreign body type
Define Resolution
the complete restoration of normal tissue architecture without scarring through regeneration
define regeneration
when existing cells or stem cells are proliferating to restore damaged tissues
define organisation
replacing damaged tissues using granulation tissue
define scar formation
form of tissue repair occurring in tissues unable to regenerate or too severely damaged to adequately support regeneration
define fibrosis
the deposition of excessive collagen in response to chronic inflammation or tissue necrosis
After inflammation, repair occurs in which two processes ?
regeneration or scar formation
define tissue repair
restoration of tissue architecture and function
not resolution
define regeneration
the proliferation of residual cells within a tissue to restore the damaged tissue
what does the ability of a tissue to regenerate depend on? (3)
- intrinsic proliferative capacity
- presence of stem cells
- integrity of supporting connective tissue framework
regarding regeneration and scar formation, what are the differences in origin and end point?
regeneration
the process that results in resolution
- from mild injury
scar formation
connective tissue deposition
- from severe injury
for an example, give two mechanism in which the liver regenerates.
proliferation of existing hepatocytes
replacing cells by progenitor stem cells
ONLY IF EXTRA-CELLULAR MATRIX IS INTACT
what condition from alcohol use leads to scarring of the liver with impaired regeneration and nodules of tissue?
cirrhosis
what condition includes scarring of the lungs?
fibrosis - damage to connective tissue
what is a scar?
the end result of replacement of any tissue parenchyma by collagen
define ischaemia
an inadequate blood supply to an organ or part of the body, especially the heart muscles
3 steps in scar tissue formation
inflammation
cellular proliferation
- angiogenesis
- fibroblasts - deposit collagen
maturation
-granulation tissue formation (organisation)
- cellular migration - TGFb in granulation tissue
- deposition of connective tissue
maybe wound contraction if its a large surface
what type of macrophage is involved in scar tissue formation?
M2 alternatively activated macrophage
how is angiogenesis regulated?
the release of angiogenic factors
stimulate blood vessel growth
how does granulation tissue form?
from fibroblast proliferation
what is the process of wound contraction
fibroblasts convert into
- myofibroblasts like smooth muscle and contract
what is the purpose of wound contraction
to reduce the wound size
what are the two processes which come under cutaneous wound healing?
primary and secondary intention
what is primary intention healing?
when the wound is thin, small and little fibrosis
what is secondary intention healing?
when the wound is large, clot, more granulation tissue
wound contraction
what if there is is inadequate granulation tissue formation?
leads to wound dehiscence and ulceration
what does excessive formation of tissue repair lead to?
hypertrophic scars
keloids
in acute inflammation, what does the serum exudate mainly consist of? (2)
fibrinogen
immunoglobulins
what embolism can only occur in individuals with heart defects?
paradoxical embolisms
