Inflammation Flashcards
define inflammation
coordinated vascular and cellular response of the body to cell injury and cell death
how is inflammation important?
has both protective (immune) and curative features
responsible for the removal of the injurious agent and cellular debris
initiates the healing process
T/F: without inflammation we cannot heal or have normal immune function
TRUE
List some factors that can lead to inflammation
- infection
- trauma/damaged tissue
- tissue necrosis
- presence of foreign bodies
- immune reactions
- ischemia
- cancer
- chemicals
- physical agents (heat/cold, radiation)
what are the goals of inflammation?
- inactivate injurious agents
- break down and remove dead cells and other cellular debris
- initate tissue healing
List the key components of inflammation
- blood vessels
- circulating blood cells
- CT or interstitial tissue cells
- chemical mediators derived from inflammatory cells or plasma cells
- specific ECM constituents (collagen and basement membranes)
what are the cardinal signs of inflammation?
- erythema
- heat
- edema
- pain
- loss of function
what are the events of an inflammatory reaction?
- vascular events
- vasodilation
- increased vascular permeability
what induces vasodilation during an inflammatory response?
histamine release from platelets and mast cells causing smooth muscle relaxation
explains heat and redness at site of injury
why is increased vascular permeability a key step in the inflammatory process?
allows for the passage of exudates (protein cell rich fluid) into the interstitial space
results in accumulation of blood in the area of dilation
allow for accumulation of platelets and neutrophils at site of injury
what WBCs respond during inflammation? Which one is the most important?
- neutrophils (most important)
- monocytes/monophages
- eosinophils
- basophils
- lymphocytes
- Mast cells
- langerhan cells
what is chemotaxis?
signaling molecules that tell WBCs to stop at the injury site
include:
- interleukin-8 (IL-8)
- C5a
- fMLP
- Leukotriene B4
what is diapedesis?
migration of WBCs through the endothelial lining of blood vessels
where are neutrophils the predominant cell?
predominant cell in pus
predominant leukocyte in area of injury for ~24 hrs
what is the role of monocytes in actue inflammation?
in response to inflammation signals, move to site of tissue injury and differentiate into macrophages and dendritic cells
what is the role of macrophages in acute inflammation?
these are a type of WBC that engulf and digest cellular debris, foreign substances, microbes, and cancer cells
when they arrive, actue inflammation will stop shortly after
what type of WBC produces antibodies?
lymphocytes
not included in WBC count
found in lymph
what is the role of mast cells during acute inflammation?
release histamines, serotonin, thromboxane, prostaglandins, leukotrienes, platelet activating factor, cytokines, TNF alpha
Describe how the inflammatory process goes wrong during RA
- increased TNF release from leukocytes entering due to increased synovial cell multiplication results in swollen synovium
- this attracts other WBCs which phagocytize the immune complexes
- causes the relase of metalloproteases which degrade cartilage
- causes inhibition of bone formation and stimulation of bone reabsorption
- results in formation of a pannus
what cytokine is central to many inflammatory responses?
what cell produces it
what does it do?
TNF
secreted by macrophages, mast cells, and T-lymphocytes
stimulates macrophages to produce cytotoxic molecules
list some ways inflammation can result in collateral damage to other tissues
- lack of specificity in immune response
- lysosomal enzymes
- free radicals/oxygen metabolites
- vascular damage to allow diapedesis
- phagocytosis of local cells
List the systemic effects of acute inflammation
- fever
- somnolence, malaise
- anorexia
- hypotension
- accelerated degradation of skeletal muscle
- reflect increased circulating levels of IL-1, IL-6, and TNF
define leukocytosis
increased WBC count
normal = 4000 - 10000 cells/ul
may increase to 15000-20000 cells/ul
define leukopenia
decreased WBC count
how is inflammation resolved?
- cells producing pro-inflammatory molecules produce and secrete “stop signals” or anti-inflammatory cytokines
- results in reduced production of signaling molecules (negative feedback loop)
- cells producing pro-inflammatory molecuels die
- as inflammation slows, tissue repair begins
what is difference between M1 and M2 macrophages?
M1 = encourage inflammation
M2 = anti-inflammatory and encourage tissue repair
what is the only cardinal sign of inflammation in an neutropenic disease?
fever
what are the possible outcomes of acute inflammation?
- resolution
- healing by fibrosis
- chronic inflammation
what must occur in order for complete resolution following an acute inflammatory response?
no damage to the CT framework or non-recoverable cells of any part of the body
the intracellular matrix acts as a scaffolding so it serves as a foundation for resolution, unless it has been damaged → results in scar tissue development
how is healing by fibrosis/scarring a possible outcome for an inflammatory episode?
the preinjury tissue is replaced by CT because there has been damage to the parenchymal cells
since there aren’t enough parenchymal cells, CT fills in the gaps
when you see a scar, what would you assume the intracellular matrix looks like?
disorganized with changes from the norm
how can an inflammatory episode result in chronic inflammation?
if the neutrophils and their fast-acting molecular allies cannot remove the noxious agent there is prolonged inflammatory response
end result is continuous tissue injury with ongoing attempts at repair
what is a hallmark tissue characteristic in chronic inflammation?
the tissue is infiltrated with macrophages, lymphocytes, and plasma cells
neutrophils are largely absent
what is granulomatous inflammation?
a form of chronic inflammation
caused by aggregation of macrophages
TB is a type
sometimes presens with a central abscess
compare the onset of acute vs chronic inflammation
- Acute = fast-minutes to hours
- Chronic = days
compare the cellular infiltrates in acute vs chronic inflammation
- acute = mainly neutrophils
- chronic = monocytes/macrophages, lymphocytes
compare the tissue injury and fibrosis formation in acute vs chronic inflammation
- acute = usually mild and self limited
- chronic = often severe and progressive
compare the local and systemic signs of acute vs chronic inflammation
- acute = prominent
- chronic = less prominent, may be subtle
how is diabetes related to chronic inflammation?
- adipose tissue, liver, muscle and pancreas are sites of inflammation in the presence of obesity
- this increases activity of pro-inflammatory cells which increases the release of pro-inflammatory-signaling molecules into the blood stream
- pro-inflammatory signaling molecules interfere with insulin signaling and damage pancreatic ß cells
- result is diabetes
T/F: heart disease has no relation to chronic inflammation
FALSE
it is increasingly viewed as an inflammatory disease
