Chapter 2.1 Acute Inflammation (Part 1) Flashcards
How does acute and chronic inflammation differ in regards to immune cells simplistically?
inflammation is when cells from vessel come out of vessel and into tissue space - if neutrophils are primary cell that comes into tissue space that is acute inflammation, if leukocytes are the primary cells that come into the tissue space that’s chronic inflammation
Define inflammation.
allows inflammatory cells, plasma proteins, and fluids to exit blood vessels and enter the interstitial space
acute/chronic inflammation (acute=neutrophils, chronic=lymphocytes)
What two things characterize the presence of acute inflammation?
edema (fluid from blood vessels that accumulates in tissue space- causes swelling)
neutrophils (key inflammatory cell that comes out of vessel into tissue space)
What two stimuli induce acute inflammation?
infection
tissue necrosis
What is the difference between apoptosis and necrosis?
necrosis is followed by acute inflammation
(apoptosis is not)
necrosis- body will send neutrophils in to destroy tissue then can heal
After an MI a patient may have an increase in white count. What type of cell has increased?
neutrophils bc they are generated and pushed up into dead tissue
What is the goal of acute inflammation?
neutrophils come in to eliminate the pathogen or clear necrotic debris
What does innate immunity include?
Includes the epithelium that protects body surfaces
mucus secreted by cells
complement system (series of proteins present in inactive state in serum but can be activated)
mast cells (widely distributed throughout tissue)
macrophages
neutrophils, eosinophils, basophils
(broad system that is non-specific that defends host against microbes)
Acute inflammation is mediated by several factors. Describe TLRs. Where are they present? What do they do?
present on cells of innate immune system (macrophages and dendritic cells)
recognize PAMPS (patterns of molecules present on pathogens, TLR recognize pattern and then let body know invader is present, turn on acute response) =commonly shared by microbes
What is CD14? Where is it present and what does it do?
CD14 (TLR) present on surface of macrophages
recognizes lipopolysaccharride (LPS) (which is on outer membrane of GN bacteria)
When CD14 sees that PAMP (LPS) it then activates the innate immune system.
What happens once a TLR recognizes a PAMP?
upregulates NF-kB (the molecular switch)
TLR activated, results in upregulation of NF-kB, turns on acute inflammatory response, activates immune response genes and leads to production of multiple immune mediators
Are TLRs present on cells of adaptive immunity?
Yes, also present on lymphocytes and they mediate chronic inflammation
How is Arachidonic Acid released?
released from phospholipid cell membrane by phospholipase A2
-acted on by cyclooxygenase or 5-lipooxygenase pathway
What pathway produces PG (prostaglandin)?
Describe action of PG. What type of vessels do they act on?
cyclooxygenase
PGI2, PGD2, PGE2 mediate vasodilation (at level of ARTERIOLE) and increased vascular permeability (at level of POST CAPILLARY VENULE)
PGE2 also mediates fever and pain
What does PGE2 mediate?
fever and pain
What pathway produces leukotrienes?
5-lipooxygenase pathway
What does LTB4 do?
Attracts and activates neutrophils
What four mediators activate neutrophils?
C5a, IL8, bacterial products, LTB4
What three things do LTC4, LTD4, and LTE4 do?
mediate vasoconstriction, bronchospasm, increased vascular permeability (occurs when pericytes contract increasing opening or space between endothelial cells)
(contract smooth muscle, cause it to contract), arteriole and bronchus are lined by smooth muscle
Where are mast cells found?
widely distributed throughout connective tissue
How can mast cells be activated (3 ways)?
- tissue trauma
- complement proteins C3a and C5a
- cross-linking of cell-surface IgE by antigen
Once mast cell is activated, what immediate response occurs?
Describe effect and where effect takes places.
release of preformed histamine granules
mediate vasodilation of arterioles and increased vascular permeability of post capillary venules
What is the delayed response of mast cell activation?
production of arachindonic acid metabolites, particularly leukotrienes (allow for maintenance of acute response)
Patient has mast cells which activate the acute inflammatory response and several hours later the acute inflammatory response continues, what is major mechanism by which mast cells will allow for progression of acute inflammatory response?
production of arachidonic acid metabolites, particularly leukotrienes
