lectures 30-31 Flashcards
acute and chronic inflammation (19 cards)
Explain the physiological role of inflammation.
occurs upon infections or noxious stimuli
eliminates harmful agents and necrotic cells
initiates the healing process
may injure normal tissues
- too strong of response (severe infection)
- prolonged response (persistent or recurrent infection)
- inappropriate response (self-antigens in autoimmune diseases)
Identify the characteristics of acute and chronic inflammation.
acute inflammation:
- heat (calor), redness (rubor), swelling (tumor), pain (dolor), loss of function (functio laesa)
- rapid in onset and short duration (minutes to days)
- accumulation of fluid and plasma proteins (exudation)
- accumulation of neutrophils
- TNF, IL-1, chemokine
chronic inflammation:
- insidious and of longer duration (months to years)
- tissue destruction by inflammatory cells
- vascular proliferation and fibrosis (scarring)
- influx of lymphocytes and macrophages
- IFN-ɣ by T cells and IL-12 by macrophages (synergistic stimulation)
List the events occurring during the acute inflammation response.
- Phagocytes in tissues recognize offending agents and liberate chemical mediators of inflammation
- Chemical mediators widen blood vessels (vasodilation) and increase their permeability in the vicinity
- Plasma and circulating leukocytes remove the offending agents (phagocytosis)
- Leukocytes produce signaling molecules that suppress inflammation (e.g. lipoxins)
- The damaged tissue is repaired (cell proliferation)
Distinguish vascular and cellular stages of the acute inflammatory response.
vascular stage:
- vasodilation
- increased permeability
cellular stage:
- leukocyte recruitment
- phagocytosis
Explain the sequence of events in the cellular stage.
leukocyte recruitment:
- margination
- loose attachment and rolling (selectins)
- adhesion (integrins)
- transmigration
- chemotaxis: bacterial products (lipopolysaccharides/LPS); chemokines; complement system (C5a); leukotriene B4 (LTB4)
phagocytosis:
- recognition: direct recognition of microbes by pattern recognition receptors; indirect recognition by opsonins
- engulfment: receptor-mediated endocytosis; pseudopods extend around foreign body and form a phagosome
- intracellular killing: phagolysosome (phagosome + lysosome fusion); lysosomal degradation (digestive enzymes and defensins); oxidative burst (release of toxic nitrogen and oxygen compounds such as hydrogen peroxide, hypochlorous radical, and NO)
Identify the functions of the chemical mediators of inflammation.
vasodilation and increased vascular permeability
chemotaxis
fever
pain
tissue damage
Identify the chemical mediators of inflammations responsible for each inflammatory responses (ex. vasodilation, chemotaxis, pain, etc.).
vasodilation and increased vascular permeability:
- histamine
- PAF
- C3a and C5a
- bradykinin
- leukotrienes (LTC, LTD, LTE)
- prostaglandins
- NO
chemotaxis:
- C5a
- leukotriene B (LTB)
- bacterial products (ex. LPS)
- chemokines
fever:
- IL-1, IL-6, TNF-⍺
- prostaglandins
pain:
- prostaglandins
- bradykinin
tissue damage:
- lysosomal enzymes
- reactive oxygen species (ROS)
- NO
Describe the mechanism of the reciprocal relationship between macrophages and lymphocytes in chronic inflammation.
macrophages and lymphocytes persistently stimulate one another until the triggering antigen is removed
- lymphocytes activated by macrophages presenting antigen fragments
- activated lymphocytes release mediators including IFN-ɣ
- IFN-ɣ activates macrophages
- activated macrophages release cytokines including IL-12
- IL-12 further activates lymphocytes
Describe the cause and the mechanism of the granulomatous inflammation.
formation of granuloma:
- small (1-2 mm) lesion of epithelioid macrophages surrounded by lymphocytes
caused by offending agents not easily controlled b other inflammatory mechanisms:
- foreign bodies such as splinters, sutures, silica, and asbestos
- microorganisms that cause TB, syphilis, sarcoidosis, deep fungal infections, and brucellosis
foreign body giant cells:
- multi-nucleated cells formed by coalesced macrophages
- encapsulate and isolate the offending agents
What are the two cell types most responsible for chronic inflammation?
a. basophils and lymphocytes
b. neutrophils and macrophages
c. macrophages and lymphocytes
d. basophils and macrophages
e. neutrophils and lymphocytes
c. macrophages and lymphocytes
Which of the following does not belong to the classic signs of inflammation?
a. Swelling
b. Pain
c. Redness
d. Heat
e. Scarring
e. scarring
The vascular change upon inflammation increases leukocyte settling along the inner surface of the blood vessels, which is called _____________.
a. vasodilation
b. edema
c. margination
d. extravasation
e. transcytosis
c. margination
Which of the following plasma proteins causes pain?
a. C3b
b. Bradykinin
c. Fibrinopeptides
d. Thrombin
e. C3a and C5a
b. bradykinin
The mediators of inflammation are matched with the enzymes responsible for their production. Which pair is incorrect?
a. Bradykinin – kallikrein
b. Leukotrienes – cyclooxygenase
c. Platelet activating factor (PAF) – phospholipase A2
d. Nitric oxide (NO) – inducible nitric oxide synthase
e. Fibrinopeptides – thrombin
b. Leukotrienes – cyclooxygenase
What are the key cytokines responsible for acute inflammation?
a. IFN-γ and IL-12
b. IFN-γ and TNF-α
c. IFN-γ and IL-1
d. TNF-α and IL-12
e. TNF-α and IL-1
e. TNF-α and IL-1
Which of the following mediators may cause tissue damage?
a. Lysosomal enzymes
b. Reactive oxygen species (ROS)
c. Nitric oxide (NO)
d. All of the above
e. None of the above
d. All of the above
Which of the following is not responsible for killing of the engulfed bacteria in phagolysosomes?
a. α2-macroglobulin
b. Lysosomal proteases
c. Defensins
d. Hydrogen peroxide (H2O2)
e. Hypochlorous radical (HOCl*)
a. α2-macroglobulin
What cells are commonly found in granulomas?
a. cancer cells and lymphocytes
b. cancer cells and neutrophils
c. epithelioid macrophages and lymphocytes
d. epithelioid macrophages and neutrophils
e. neutrophils and lymphocytes
c. epithelioid macrophages and lymphocytes
What do pattern recognition receptors of leukocytes recognize directly?
a. Selectins and integrins
b. Chemokines
c. Opsonins
d. Histamines
e. Microbes
e. Microbes
