Inflammation Flashcards
What is inflammation
Inflammation is the response of vascularized tissue that delivers leucocyte and molecules of host from circulation to the site of infection and cell damage in order to eliminate the offending agent
What are the 5 R of inflammation
Recognition
Recruitment
Removal
Regulation
Repair
What are cardinal signs of inflammation
Calor
Rubor
Dolar
Tumour
Functional loss
Describe vascular events of inflammation
Transient vasoconstriction
Vasodilation
Describe vascular events of inflammation
Transient vasoconstriction
Vasodilation
Causes of increased vascular permeability
Endothelial cell contraction
Endothelial injury
Increased transcytosis of protein
Leakage from new blood vessels (angiogenesis)
Describe cellular events of inflammation
Recruitment of WBC
Activation of WBC
Phagocytosis
Killing and degradation
Steps of leucocyte recruitment
Margination and rolling
Adhesion
Transmigration
Migration to interstitial tissue
Rolling is mediated by which adhesion molecules
Selectins
What are the 3 selectins
E selectin
P selectin
L selectin
What molecules mediate adhesion
Integrins join on ligand on cell endothelium
What is diapedesis
After being arrested on the endothelial
surface, leukocytes migrate through the vessel wall primarily by squeezing between cells at intercellular junctions.
This extravasation of leukocytes, called diapedesis,
What is chemotaxis
After extravasating from the blood, leukocytes move toward sites of infection or injury along a chemical gradient by a process called chemotax
What are chemotactic agents
Bacterial products, particularly peptides with N-formylmethionine termini
• Cytokines, especially those of the chemokine family
• Components of the complement system, particularly C5
• Products of the lipoxygenase pathway of arachidonic
acid (AA) metabolism, particularly leukotriene B4
(LTB4)
Why are neutrophils abundant in acute inflammation
- They are most numerous
- React rapidly to cytokines
- Attach firmly to adhesion molecules
- They short lived
Leucocyte activation enhances the following function
1.Phagocytosis
2.Intracellular destruction of phagocytosed microbes and dead
cells
3. Liberation of substances that destroy extracellular microbes
and dead tissues,
4.Production of mediators, including arachidonic acid metabolites and cytokines, that amplify the inflammatory reaction, by recruiting and activating moreleukocytes
What are steps of phagocytosis
(1) recognition and attachment of the particle to the ingesting
leukocyte;
(2) engulfment, with subsequent formation of a phagocytic vacuole; and
(3) killing and degradation of the ingested
material.
What is opsonisation
material.
Leukocytes bind and ingest most microorganisms and
dead cells by means of specific surface receptors. Some of
these receptors recognize components of the microbes and
dead cells and other receptors recognize host proteins,
called opsonins, that coat microbes and target them for
phagocytosis (the process called opsonization).
What happens during oxidative burst
Increased oxygen consumption
Glycogen catabolism
Glucose oxidation
Production of ROS
What are neutrophlic extra-cellular trap NEXT
These are fibrillar network produced by neutrophils
These traps provide high concentration of antimicrobial substance at site of infection and prevent spread of microbes by trapping them
Clinical examples of leucocyte induced injury
Acute respiratory distress
syndrome
Acute transplant rejection Lymphocytes; antibodies and
complement
Asthma Eosinophils; IgE antibodies
Glomerulonephritis Antibodies and complement;
neutrophils, monocytes
Septic shock Cytokines
Chronic
Rheumatoid arthritis Lymphocytes, macrophages;
antibodies?
Asthma Eosinophils; IgE antibodies
Atherosclerosis Macrophages; lymphocytes?
Chronic transplant rejection Lymphocytes, macrophag
What can be the defects in leucocyte functions
LEUCOCYTE ADHESION DEFECT: type 1 due to defective synthesis of the CD18 β
Type 2 : due to by a defect in fucose
metabolism resulting in the absence of sialyl–Lewis X,
the oligosaccharide on leukocytes that binds to selectins
on activated endothelium.
DEFECT IN MICROBIAL ACTIVITY : eg chronic granulomatous disease
DEFECTS IN PHAGOLYSOSOME FORMATION
What are morphological patterns of acute inflammation
- SEROUS INFLAMMATION is characterized by the outpouring of a watery, relatively protein-poor fluid that, depending on the site of injury, derives either from the plasma or
from the secretions of mesothelial
cells lining the peritoneal, pleural, and pericardial cavities. - FIBRINOUS INFLAMMATION occurs as a consequence of
more severe injuries, resulting in greater vascular permeability that allows large molecules (such as fibrinogen) to
pass the endothelial barrier - SUPPURATIVE (PURULENT) INFLAMMATION and abscess
formation. These are manifested by the collection of
large amounts of purulent exudate (pus) consisting of
neutrophils, necrotic cells, and edema fluid.
4.• AN ULCER is a local defect, or excavation, of the surface
of an organ or tissue that is produced by necrosis of cells
and sloughing (shedding) of necrotic and inflammatory
tissue
What are performed , cell derived inflammatory mediators
Histamine
Serotonin
