HISTOPATH LEC - LESSON 4 (INFLAMMATION AND REPAIR) Flashcards
a response of vascularized tissues to infectious organisms and / or tissue damage that brings cell and molecules of host defense from the circulation to the sites where they are needed, in order to eliminate the offending agents.
inflammation
the initial, rapid response to infections and tissue damage.
acute inflammation
typically develops within minutes or hours and is of short duration. it lasts for several hours to a few days.
acute inflammation
main characteristics of acute inflammation
- exudation of fluid and plasma proteins (edema)
2. emigration of leukocytes, predominantly neutrophils
exudation of fluid and plasma proteins
edema
neutrophils are also called
polymorphonuclear leukocytes
this is a protracted phase which has longer duration.
chronic inflammation
associated with more tissue destruction, the presence of lymphocytes and macrophages, the proliferation of blood vessels and the deposition of connective tissue.
chronic inflammation
cellular infiltrate of acute inflammation
mainly neutrophils
feature of tissue injuries of acute inflammation
self limiting and usually mild
cellular infiltrate of chronic inflammation
monocytes, macrophages, lymphocytes
feature of tissue injuries of chronic inflammation
severe and progressive
defined as the local response of living mammalian tissues to injury due to any agent.
inflammation
enumerate infective agents
bacteria, virus and their toxins, fungi and parasites
enumerate immunologic agents
cell mediated and antigen - antibody reaction
enumerate physical agents
heat, radiation, trauma, cold, and mechanical trauma
enumerate chemical agents
organic and inorganic poisons
enumerate inert materials
foreign bodies
five cardial signs of inflammation
- rubor
- tumor
- calor
- dolor
- functio laesia
rubor means
redness
tumor means
swelling
calor means
heat
dolor means
pain
functio laesia means
loss of function
this is the reaction that takes place within the inflammation site
immune response
type of cell that is responsible for making the extracellular matrix and collagen.
fibroblasts
non specific, first line of defense
innate immune response
consist of physical, chemical and cellular defenses
innate immune response
main purpose of innate immune response
immediately prevent the spread and movement of foreign pathogens throughout the body
acquired / specific immunity and is only found in vertebrates
adaptive immune response
second line of defense
adaptive immune response
main purpose of adaptive immune response
attack non self pathogens but can sometimes attack itself, make errors and cause autoimmune diseases
cells of the innate immune response (7)
natural killer cells, macrophages, neutrophils, dendritic cells, mast cells, basophils and eosinophils
cells of adaptive immune response (2)
t and b lymphocytes
first to respond to allergies
basophils
second to respond to allergies
eosinophils
tissue necrosis can be due to what
ischemia, trauma and physical and chemical injury
exogenous foreign bodies include
splinters, dirt and sutures
endogenous foreign bodies include
urate crystals, cholesterol crystals and lipids
urate crystals causes
gout
cholesterol crystals causes
atherosclerosis
lipid causes
obesity associated with metabolic syndrome
first step in inflammation
recognition of microbes / damaged cells
steps in acute inflammation
a. blood vessel reaction
b. leukocyte recruitment
c. phagocytosis and clearing of offending agent
d. termination of response
blood vessel reaction includes
- vascular reaction of acute inflammation consists of change in the flow of blood.
- change in the permeability of blood vessels.
vasodilation creates what for cells
increased pathway
refers to the engulfment of the bacteria / foreign material
phagocytosis and clearing of offending materials
three steps in phagocytosis
- recognition and attachment of particle to be ingested by the leukocyte.
- engulfment with subsequent formation of phagocytotic vacuole.
- killing / degradation of ingested material
these are substances that initiate and regulate inflammatory reactions
mediators of inflammation
this mediator includes histamine and serotonin
vasoactive amines
these are mediators for vasodilation and increased permeability
vasoactive amines
this mediator includes prostaglandins and leukotrienes
arachidonic acid metabolites
this mediator is involved in vascular reaction, leukocyte chemotaxis, and other reaction of inflammation
arachidonic acid metabolites
antagonized by lipoxins
arachidonic acid metabolites
proteins produced by many cell types and usually act short range
cytokines
when this acute inflammation mediator is activated, it leads to the generation of multiple breakdown of products
complement system proteins
produced by proteolytic cleavage of precursors
kinins
morphologic pattern of acute inflammation
- serous inflammation
- fibrinous inflammation
- purulent inflammation
- ulcers
this type of infection is brought by microorganisms that are difficult to eradicate.
persistent infection
auto antigens evoke a self perpetuating immune reaction that results in chronic tissue damage and inflammation
autoimmunity
immune response against common environmental substances (e.g., bronchial asthma)
allergy
prolonged exposure to toxic agents causes what
silicosis and atherosclerosis
morphologic patterns of chronic inflammation
- infiltration with many mononuclear cells, which may include macrophages, lymphocytes and plasma cells.
- tissue destruction induced by the persistent offending agent or by the inflammatory cells.
- attempts at healing by connective tissue replacement of damaged tissue, accomplished by angiogenesis and in particular, fibrosis.
this mediator is the dominant cell in most chronic inflammatory reactions
macrophages
it secretes cytokines and growth factors that act on various cells
macrophages
it destroys foreign tissues and invaders
macrophages
it activates t lymphocytes
macrophages
abundant in immune reactions, mediated by IgE and in parasitic infection.
Eosinophils
mediator of chronic inflammation. it releases mediators such as histamine and prostaglandins
mast cells
what are the four systematic effects of inflammation
- fever
- production of acute phase proteins
- leukocytosis
- septic shock
this happens when there is a fall in blood pressure and is induced by high levels of TNF and other cytokines
septic shock
the process wherein some issues are able to replace the damaged components and essentially return to a normal state
regeneration
what tissues can undergo regeneration
epithelia of the skin, intestines and liver
this occurs when injury are incapable of complete reinstitution
repair
regeneration of liver is triggered by _______ and _______ produced in response to loss of liver mass and inflammation
cytokines and growth factors
what are the two ways regeneration may occur?
- proliferation by surviving hepatocytes
2. repopulation from progenitor cells (stem cells)
scar formation is a response that ______ rather than restores the tissue.
patches
this term is most often used in connection to wound healing in the skin
scar
this term can be used to describe the replacement of parenchymal cells in any tissue by collagen.
scar
steps in repair
- angiogenesis
- formation of granulation tissue
- remodeling of connective tissue
this refers to the formation of new blood cells which supply nutrients and oxygen needed to support the repair process.
angiogenesis
this step in repair refers to the migration and proliferation of fibroblasts and deposition of loose connective tissue.
formation of granulation tissue
this step in repair refers to the maturation and reorganization of the connective tissue to produce the stable fibrous scar.
remodeling of connective tissue
this process involves both epithelial regeneration and the formation of connective tissue scar
skin wound healing
this healing refers to when the injury involves only the epithelial layer, and the principal mechanism of repair is epithelial regeneration
healing by first intention
this healing refers to when cells or tissue loss is more extensive and the repair process involves a combination of regeneration and scarring.
healing by second intention
steps in healing by second intention
- the fibrin clot is larger and there is more exudate and necrotic debris in the wounded area.
- inflammation is more extensive because large tissue defects have a greater volume of necrotic debris, exudate and fibrin that must be removed.
- larger defects require a greater volume of granulation tissue to fill in the gaps and provide underlying framework for the regrowth of the tissue.
- wound contraction generally occurs in large surface wounds.
- contraction is mediated by a network of myofibroblasts
these are modified fibroblasts which exhibit many of the ultrastructural and functional features of contractile smooth muscle cells.
myofibroblasts
best example of regeneration
liver
mediators of acute inflammation
vasoactive amines, arachidonic acid metabolite, complement system proteins, kinins, cytokines
mediators of chronic inflammation
macrophages, lymphocytes, eosinophils, mast cells and neutrophils
causes of chronic inflammation
persistent infection, autoimmunity, allergy, prolonged exposure to toxic agents