[P] Week 2: Inflammation and Repair - Part 2 Flashcards
Enumerate the steps of phagocytosis
- Recognition and Attachment
- Engulfment
- Killing and Degradation
STEPS OF PHAGOCYTOSIS
Involves the recognition and attachment of the particle to be
ingested by the leukocyte
Recognition and Attachment
STEPS OF PHAGOCYTOSIS
this receptors enable phagocytes to bind and ingest microbes
Mannose receptors, scavenger receptors, and receptors
for various opsonins
STEPS OF PHAGOCYTOSIS
Consists of the extension of the cytoplasm around the particle, and the plasma membrane pinches off to form an intracellular vesicle called the PHAGOSOME, which encloses the particle.
Engulfment
STEPS OF PHAGOCYTOSIS - Engulfment
The phagosome then fuses with a lysosomal granule, which discharges its contents into the?
PHAGOLYSOSOME
STEPS OF PHAGOCYTOSIS
Involves the killing of the microbe and degradation of the
ingested material
Killing and degradation
STEPS OF PHAGOCYTOSIS
Killing of microbes is accomplished by? enumerate
- Reactive oxygen species (ROS)
- Reactive nitrogen species (mainly derived from and nitric oxide (NO))
STEPS OF PHAGOCYTOSIS - Killing and degradation
produced by the rapid assembly and activation of a multicomponent oxidase nicotinamide adenine dinucleotide phosphate (NADPH) oxidase which oxidizes reduced NADPH and, in the process, reduces oxygen to superoxide anion–making it highly reactive
Reactive Oxygen Species
STEPS OF PHAGOCYTOSIS - Killing and degradation
superoxide from the NAPDH oxidization can be converted to?
hydrogen peroxide
STEPS OF PHAGOCYTOSIS - Killing and degradation
Hydrogen peroxide may not efficciently kill microbes, so it should be combined with?
- myeloperoxidase (MPO)
- Halide (such as chloride to convert to HCl)
STEPS OF PHAGOCYTOSIS - Killing and degradation
give an example of an ROS
hydrogen peroxide myeloperoxidase (H2O2-MPO) halide system
most potent bactericidal system of the neutrophils
STEPS OF PHAGOCYTOSIS - Killing and degradation
a soluble gas produced from arginine by the action of nitric oxide
synthase (NOS), also participates in microbial killing.
Reactive Nitrogen Species: Nitric Oxide
STEPS OF PHAGOCYTOSIS - Killing and degradation
what are the three types of NOS
- endothelial nitric oxide synthase (eNOS)
- neuronal nitric oxide synthase (nNOS)
- inducible nitric oxide synthase (iNOS)
STEPS OF PHAGOCYTOSIS - Killing and degradation
constitutively expressed at low levels, and the NO they generate functions to maintain vascular tone and as neurotransmitter, respectively
eNOS and nNOS
STEPS OF PHAGOCYTOSIS - Killing and degradation
This NO is type that is involved in microbial killing, is induced when macrophages are activated by cytokines.
iNOS
STEPS OF PHAGOCYTOSIS - Killing and degradation
in macrophage what is the mechanism of NO so that it will attack and damage the microbe
NO reacts with a superoxide to
generate the highly-reactive free radical PEROXYNITRITE
NO + Superoxide = Peroxynitrite
STEPS OF PHAGOCYTOSIS - Killing and degradation
Granules, may be categorized as?
- Smaller specific (secondary) granules
- Larger azurophilic (primary) granules
STEPS OF PHAGOCYTOSIS - Killing and degradation
this granule contains the:
lysozyme, collagenase, gelatinase, lactoferrin, plasminogen activator, histaminase, alkaline phosphatase
Secondary granules
STEPS OF PHAGOCYTOSIS - Killing and degradation
this granule contains the:
myeloperoxidase, bactericidal proteins such as lysozymes and defensins, acid hydrolases, and a variety of neutral proteases such
as elastase, cathepsin G, non-specific collagenase, and
proteinase 3
Primary granules
STEPS OF PHAGOCYTOSIS - Killing and degradation
this granule contains the:
defencins, cathelicidins, lysozyme, lactoferrin, and the major basic
protein, which is usually present in eosinophils
Other microbicidal granule
This mechanism are present in order to combat the action of these free radicals
Antioxidant Mechanism
Antioxidant Mechanism may be in the form of?
- Superoxide dismutase
- Catalase
- Glutathione peroxidase
- Ceruloplasmin
- Transferrin
Extracellular fibrillar networks that provide a high concentration of antimicrobial substances at sites of
infection and trap microbes, helping to prevent their spread
NEUTROPHIL EXTRACELLULAR TRAPS (NETs)
LEUKOCYTE-MEDIATED TISSUE INJURY
Leukocytes are important causes of injury to normal cells and tissues under several circumstances:
As part of the normal defense reaction against infectious
microbes, when ____ tissues suffer collateral
damage
Adjacent
LEUKOCYTE-MEDIATED TISSUE INJURY
Leukocytes are important causes of injury to normal cells and tissues under several circumstances:
In some infections that are difficult to eradicate, such as tuberculosis, and certain viral diseases, the ____ ____ ____ contributes more to the pathology that does the microbe itself.
prolonged host response
LEUKOCYTE-MEDIATED TISSUE INJURY
Leukocytes are important causes of injury to normal cells and tissues under several circumstances:
When the inflammatory response is inappropriately directed against host tissues, as in certain _____ _____
Autoimmun diseases
LEUKOCYTE-MEDIATED TISSUE INJURY
Leukocytes are important causes of injury to normal cells and tissues under several circumstances:
When the host reacts excessively to against usually harmless environmental substance, as in ____ ____, including asthma
Allergic diseases
OTHER FUNCTIONAL RESPONSES OF ACTIVATED LEUKOCYTES
Activated leukocytes play several other roles in host defense, enumerate
- Produce Cytokines (either amplify or limit inflammatory reactions)
- Produce Growth Factors (stimulate the proliferation of endothelial cells and fibroblasts and the synthesis of collagen, and enzymes that remodel connective tissues.)
- Production of Th17 (IL-17) cells (induces the secretion of chemokines that recruit other leukocytes)
KINDLY CHECK
CLINICAL EXMPALES OF LEUKOCYTE INJURY, ACUTE AND CHRONIC PLEASE LANG
DEFECT IN LEUKOCYTE FUNCTIONS (GENETIC)
Match
- Leukocyte adhesion def 1
- Leukocyte adhesion def 2
- Chronic granulomatous disease
- MPO def
- Chediak Higashi syndrome
A. Mutations in fucosyl transferase
B. Decrease oxidative burst
C. Mutations in B chain of CD11/CD18 integrins
D. Mutations affecting protein involved in lysosomal membrane traffic
E. Defective MPO H2O2 system
- C
- A
- B
- E
- D
DEFECT IN LEUKOCYTE FUNCTIONS (ACQUIRED
Match
- Bone marrow suppression
- Diabetes, malignancy, sepsis, chronic dialysis
- Leukemia, anemia, sepsis,
diabetes, malnutrition
A. Adhesion and Chemotaxis
B. Phagocytosis and Microbicidal activity
C. Production of Leukocyte
- C
- A
- B
DEFECTS IN LEUKOCYTE FUNCTION
defect in phagolysosome function seen in?
Chediak-Higashi syndrome
DEFECTS IN LEUKOCYTE FUNCTION
Inherited defects in ____ ____ like in chronic granulomatous disease wherein there is inherited defects in
the genes encoding components of phagocyte oxidase
microbicidal activity
DEFECTS IN LEUKOCYTE FUNCTION
may lead to marrow suppression
Acquired deficiencies
DEFECTS IN LEUKOCYTE FUNCTION
cells in tissue that serve important functions in initiating acute inflammation.
Mast cells and macrophages
DEFECTS IN LEUKOCYTE FUNCTION
defect of integrins and selectin ligands which may lead to recurrent bacterial infection.
Inherited defect in leukocyte adhesion
TERMINATION OF ACUTE INFLAMMATORY RESPONSE
When the cells were able to control the infection, there must be a?
termination of the inflammatory response
TERMINATION OF ACUTE INFLAMMATORY RESPONSE
Note that inflammation is a?
DOUBLE-EDGED SWORD
(it is protective but it can also cause damage to the normal cells or tissues)
TERMINATION OF ACUTE INFLAMMATORY RESPONSE
nfammation declines after the offending agents are
removed simply because the mediators of inflammation: ENUMERATE
- Are produced in rapid burst as long as the stimulus persists
- Have short half-lives
- Are degraded after their release (easily destroyed)
TERMINATION OF ACUTE INFLAMMATORY RESPONS
it should produce what anti-inflammatories?
- anti-inflammatory lipoxins
- anti-inflammatory cytokines
- anti-inflammatory lipid mediators
MEDIATORS OF INFLAMMATION
substances that initiate
and regulate inflammatory reactions.
Inflammatory mediators
MEDIATORS OF INFLAMMATION
Mediators are generated either from?
cells or from plasma
proteins.