Title: What is inflammation?
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3- What is inflammation?
- What are the cardinal signs?
- What are the vascular changes in Acute
Inflammation? -
- What are the cellular changes in Acute
Inflammation?
4INFLAMMATION
- It is a complex reaction to injurious agents such
as microbes and damaged, usually necrotic, cells
that consist of - Vascular responses,
- Migration and activation of leukocytes and
- Systemic reactions
- the reaction of a tissue and its
microcirculation to injury
5TISSUE INJURY
- Physical
- Chemical
- Biological
- Ischaemia
- Neoplasm
6Inflammation and repair are fundamentally
protective but may be potentially harmful
7TYPES
- Acute Inflammation of short duration, edema and
leukocyte emigration esp. Neutrophils - Chronic Inflammation of longer duration,
Lymphocytes, Macrophages, Blood vessel
proliferation, Fibrosis and Tissue necrosis
8COMPONENTS
- Fluid Plasma proteins
- Cells
- Circulating N, L, M, E, B
- Connective tissue Mast cells, Fibroblasts,
Macrophages - Extracellular matrix
- Structural Collagen, Elastin
- Adh Glycoproteins Fibronectin, Laminin,
Tenascin etc - Proteoglycans
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13SIGNS
- Rubor (redness)
- Tumor (swelling)
- Calor (heat)
- Dolor (pain)
-
-Cornelius Celsus - Functio laesa (loss of function)
- -
Rudolf Virchow
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20Ilya Mechnikov
( Elie Metchnikoff ) and the Phagocyte
Cells
- In 1882, the Russian scientist Ilya Mechnikov was
working in Messina, Italy, studying the larvae of
the sea star. When he inserted a thorn into a
larva, something weird happened. Mechnikov
noticed strange cells gathering at the point of
insertion. The cells surrounded the thorn, eating
any foreign substances that entered through the
ruptured skin. Mechnikov was thrilled. He decided
to name these new cells phagocytes from the Greek
words meaning "devouring cells."
21Paul Ehrlich and the Side-chain Theory
- At the end of the nineteenth century, the German
scientist Paul Ehrlich developed the "side-chain
theory" to explain immunity and how antibodies
were formed. Although we now know that some of
his ideas were incorrect, this theory allowed him
to accomplish important work and provided the
groundwork for later researchers in this field. - Ehrlich argued that all cells have a wide variety
of special receptors that he called side-chains.
He thought that these receptors worked like
gatekeepers or locks for the cell. Each
receptor/side-chain had a unique structure, and
only substances matching this structure were
allowed to enter the cell. - The side-chain receptors primary function was to
absorb nutrients for the cell. Unfortunately, the
receptors also allowed many toxic substances to
enter. According to Ehrlich, the body defended
itself against these toxins in the following way
When a cell was attacked by a toxin, it started
to produce excess side-chains matching the toxin.
These excess side-chains then were released,
flooding the body and neutralizing free toxins by
attaching to them. The toxin was wiped out and
remaining healthy cells protected.
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23Historical CommentaryNature Immunology 9, 705 -
712 (2008) doi10.1038/ni0708-705Immunology's
foundation the 100-year anniversary of the Nobel
Prize to Paul Ehrlich and Elie MetchnikoffStefan
H E KaufmannAbstractOne hundred years ago the
birth of immunology was made official by the
Nobel Prize award to Elie Metchnikoff and Paul
Ehrlich. Metchnikoff discovered phagocytosis by
macrophages and microphages as a critical
host-defense mechanism and thus is considered the
father of cellular innate immunity. Ehrlich
described the side-chain theory of antibody
formation and the mechanisms of how antibodies
neutralize toxins and induce bacterial lysis with
the help of complement and thus is considered one
of the fathers of humoral adaptive immunity.
Despite many discordant discussions in the
initial phase after these discoveries, innate and
adaptive responses are now known to be
complementary partners in producing robust
immunity.
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26ACUTE INFLAMMATION
- Changes in vascular caliber
- Changes in vascular structure
- Emigration of leukocytes, accumulation at site of
injury and their activation
27Changes in Vascular Flow and Calibre
- Vasodilatation and increased blood flow
- First involves arterioles
28Increased Vascular permeability
- Leads to escape of protein rich fluid into the
extravascular tissue - Endothelial changes lead to increased permeability
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43The series of events are
- Vasodilation leads to greater blood flow to the
area of inflammation, resulting in redness and
heat. - Vascular permeability endothelial cells become
"leaky" from either direct endothelial cell
injury or via chemical mediators. - Exudation fluid, proteins, red blood cells, and
white blood cells escape from the intravascular
space - Vascular stasis slowing of the blood in the
bloodstream
44- An exudate is an inflammatory extravascular fluid
that has a high protein concentration, cellular
debris, and a specific gravity above 1.020 - A transudate is a fluid with low protein content
(most of which is albumin) and a specific gravity
of less than 1.012
45Pus, a purulent exudate, is an inflammatory
exudate rich in leukocytes (mostly neutrophils),
the debris of dead cells and, in many cases,
microbes.