Inflammation 1 Flashcards
What are the three main processes that occur at the site of inflammation?
Vasodilation
Vascular leakage and edema
Leukocyte emigration to extravascular tissues
What is exudation?
Escape of fluid, proteins, and blood cells from the vascular system into the interstitial tissue or body cavities
What is the difference between a transudate and exudate?
Exudate - high protein content, cellular debris, indicates inflammation
Transudate - low protein content, no cell material, indicates osmotic or hydrostatic imbalance
How does vascular congestion and localized redness develop?
Loss of fluid and increased vessel diameter lead to slower blood flow, concentration of red cells in small vessels and increased viscosity
This results in stasis
What are the major mediators of endothelial cell retraction and what kind of response is it?
Histamine, Bradykinin, Leukotrienes
Immediate transient response
What is transcytosis?
Increased transport of fluids and proteins through the endothelial cell
What to processes promote vascular leakage?
Retraction of endothelial cells
Endothelial injury
What three processes make up the movement of leukocytes in the lumen?
Margination
Rolling
Adhesion
What factors mediate rolling?
Selectins expressed on endothelium, Platelets, and leukocytes
What regulates the expression of selectins and their ligands?
Cytokines produced in response to infection and injury
What mediates adhesion?
Integrins
Bind more firmly than selectins, stops leukocytes at the site of inflammation
What molecules are involved in transmigration?
CD31 or PECAM-1
What are the main chemotaxis agents for leukocytes?
IL-8
C5a
LTB4
Bacterial agents
What are the three steps of phagocytosis?
Recognition and Opsonization
Engulfement
Killing or degradation
What are the major opsonins?
IgG
C3b
Mannose-binding lectin
Describe the oxygen-dependent mechanism for killing microbes employed by phagocytes.
NADPH oxidase generates superoxide in the phagolysosome
Superoxide is converted to H2O2
MPO converts H2O2 to hypochlorite (bleach) that destroys microbes
What are the two actions of NO in inflammation?
Relaxes vascular smooth muscle and promotes vasodilation
Inhibitor of the cellular component of inflammatory response
What are the three types of NO?
eNOS and nNOS are constitutively expressed at low levels
iNOS is induced when macrophages and neutrophils are activated by cytokines or microbial products
What are the oxygen-independent systems of killing?
Lysozyme
Lactoferrin
Major basic protein
What is Chediak-Higashi disease?
Autosomal recessive inheritance
Neutropenia with recurrent infections
Oculocutaneous albinism
Giant lysosomes and melanosomes
What is Chronic Granulomatous disease?
X-linked recessive
Recurrent infections by catalase-producing microorganisms
Basic defect is NADPH oxidase
What are the characteristics of serous inflammation?
Low MW proteins
Clear, yellow fluid
No cells
E.g. blisters from burns or viral infections
What are the characteristics of fibrinous inflammation?
Contains fibrin
Coats a surface, no cells
Fibrinous pneumonia
What is an ulcer?
Local defect of the surface of an organ or tissue that is produced by necrosis of cells and sloughing of necrotic or inflammatory tissue
What is a purulent exudate?
Contains large proteins like albumin and fibrin, as well as neutrophils
What is an eosinophilc exudate?
Eosinophil is prominent
Characteristically occurs in type 1 hypersensitivity
What is a hemorrhagic exudate?
Damage to endothelial cells and vessel walls allow RBCs to leak into the surrounding tissue
E.g. Rocky Mountain Spotted Fever
What is cellulitis?
A diffuse area of acute inflammation composed of edema fluid, bacteria and neutrophils spread through the tissue
E.g. S. pyogenes and flesh-eating infections
What is a psueomembranous exudate?
Injury results in necrosis of affected tissue lining a surface
Results in the formation of a mebmrane composed of fluid, proteins, neutrophils, RBCs and necrotic tissue
E.g. C. diff
What is a mucinous exudate?
Inflammation in tissue containing abundant mucin-secreting glands is likely to stimulate mucus secretion
E.g. bronchitis
What is an abscess?
Focus of acute inflammation composed of pyogenic exudate and necrotic tissue
E.g. S. aureus and K. pneumoniae
What is a furuncle and carbuncle?
Subcutaneous abscess, usually arising near a hair follicle
Carbuncle - coalesced furuncles
