INFLAMMATION AND HEALING Flashcards
CARDINAL SIGN :
Rubor (redness)
Tumor (swelling)
Calor (heat)
Dolor (pain)
redness
RUBOR
swelling
tumor
pain
dolor
heat
calor
The earliest acceptable definition
of inflammation was given by —-
as the process that occur in a living tissue when it is injured provided that the injury is not of such a degree as to at once destroy its structure and vitality.
Bourdon-Sanderson
Is a protective mechanism in that protective factor such as
antibodies, complement and phagocytic cells normally confined to the
bloodstream gain access at localized tissue sites to destroy foreign invaders.
Inflammation
purpose Inflammation
- is to minimize the effect of the irritant or injury
*to heal the damaged tissue and
*restore the affected tissues to normal
The etiology of inflammation varies and includes both living and nonliving agents such as:
bacteria, fungi, viruses, metazoan parasites, protozoa, immunologic injury, trauma, heat, cold, toxins or poisons and irradiation.
described much of the descriptions on the initial inflammatory
reactions in 1882.
Conheim
the initial response involves the endothelia of capillary bed
(arteriole, venule, intercommunicating vessels and the true
capillaries)
After an initial arteriolar constriction, there occur sustained
dilatation of all small blood vessels
The overload of venous drainage
leads to passive congestion that also contributes to
vasodilation
Leucocytes then begin to
appear in the marginal plasma
stream of the venule (called
margination
and began to stick to
the walls and adhere to it for longer
periods (called
adherence
Progressively, more leucocytes
adhere to the walls until the luminal
surface of the wall become covered
with a layer of leucocytes (called
pavementing
Two phases of increased vascular permeability:
*immediate phase lasting less than an hour
*prolonged phase that last for 3-4
hours or longer if the stimulus persists
*third phase that last for several days,
although delayed in onset has been described to occur in sunburns
in tissues is accomplished by pseudopodia into the intercellular junction of endothelial cells, enlarging their opening and
squeezing through.
migration
All leucocytes have similar migration capacity, but neutrophils and eosinophils,
commonly called
polymorphs or granulocytes
What attract the leucocytes to migrate to the injured site are
chemical mediators of inflammation and this process is called
chemotaxis
are usually first, and could move
through fibrin and past tissue cells to their destination
polymorphs or granulocytes
Accumulations of such
cells may reach a peak in about 4 hours although this may vary based on the
stimuli.
i. Red blood cells, unlike leucocytes, have no a —-
they may take the advantage of the holes created by leucocytes and leak
passively into the injured area.
amoeboid capabilities
influence the previously discussed changes in vascular caliber and permeability, as well as chemotaxis of leucocytes.
Chemical mediators
The central feature of inflammation is the
infiltration of leucocytes to the
site of injury
as coined in the early ‘90s to distinguish such chemical messengers from hormones and neurotransmitter substances.
autacoid
are chemical messengers that act on vascular endothelia and leucocytes to
contribute to an inflammatory reaction.
autacoid
those coming from the outside such as
bacterial products and toxins.
Exogenous mediators
Endogenous mediators –these are synthesized by the body and may
be:
➢Plasma derived –
➢ Cell or Tissue derived –
Plasma derived – coming from the three major mediator producing systems in the plasma as
*coagulation-fibrinolytic
system,
*kinin system, and
complement system
*may be performed and stored as
granules in cells (e.g., histamine and cationic proteins) or
*newly synthesized by cells (e.g., interleukin, leukotriene, and platelet
activating factor).
Cell or Tissue derived
generated by consequent or multiple enzymic
steps involving sequential activation of molecules by limited proteolysis
(e.g., mediators formed by the complement and coagulation-fibrinolytic
systems)
Peptide mediators
– collectively called eicosanoids,
Lipid mediators
these are derived from the action of phospholipase to membrane phospholipids through the arachidonic acid pathways (lipooxygenase and cyclooxygenase
pathways)
Lipid mediators
e arachidonic acid pathways (
(lipooxygenase and cyclooxygenase
pathways)
Most of the biologically active mediators of inflammation are derived from
the systems in the plasma
Kinin, Coagulation-Fibrinolytic, and Complement
systems
and that of eicosanoids.
Effects of Autacoids
Vasodilation and Hyperemia.
most potent are as follows: Histamine released from mast cells and basophils;
Bradykinin, Prostaglandin E1 and E2, Leukotriene B4, C3 and C5 fragments of
complement, and Thromboxane.
The mediators that increase the permeability of the
microvasculature includes Histamine, Serotonin, Bradykinin, Kallikrein, Platelet
Activating Factor, Lymphokines, Anaphylatoxin (C3 and C5 fragment of
Complement), Leukotriene B4, C4 and D4, 5-HPTES (5-hydroperoxy
eicosatetranoic acid), and fibrin degradation products.
Vasopermeability
Mediators that attract neutrophils in
an inflammatory response includes C5a fragment of Complement, Leukotriene
B4, Bacterial toxins, and Platelet Aggregating Factor.
Leucocyte Emigration and Chemotaxis.
Mediators that attract neutrophils in
an inflammatory response includes
C5a fragment of Complement,
Leukotriene
B4, Bacterial toxins, and
Platelet Aggregating Factor.
he chemotactic agents
acting on monocytes and macrophages include
C5a fragment of Complement,
Leukotriene B4,
Bacterial toxins,
Cationic protein fractions of neutrophils,
Lymphokines, and
Fibrin degradation products
Lymphocytes are attracted
mainly by
Lymphokines
eosinophils are attracted by e
chemotactic factor of anaphylaxis (ECF-A) derived from mast cells, and
prostaglandin D2
Types of Exudates
- Serous exudates
- Fibrinous exudates
- Hemorrhagic exudates
- Purulent or Suppurative exudates
- Catarrhal exudates
this is primarily a clear fluid that is low in protein that
exudes from serosal or mucosal surfaces following mild irritation.
Serous exudates
The most common example is that seen in cases of “runny nose” where a clear fluid leaks from the nostrils following irritation.
these exudates usually occur in severe vascular injuries where a fluid rich in fibrinogen is produced.
Fibrinous exudates
In severe mucosal
damage where the epithelia are lost, the fibrin that accumulates may become
tightly adherent to the underlying tissue forming what is known as a
diphtheritic membrane or pseudomembrane.
The term “diphtheritic” applies to fibrinous
organization of any necrotic exudates on a mucosal surface
When the body and organ surfaces have fibrinous exudates, the fibrous
organization of the exudates forms what is called
adhesion
This is commonly seen in mucosal and serosal surfaces, most notably in the intestines, pleura, peritoneum, and synovial
membranes.
. Fibrinous exudates –
Sometimes it is
called
sanguineous exudates
when red blood cells are the predominating cellular component, the exudates are called hemorrhagic exudates.
Hemorrhagic exudates
and when coupled with a thin fluid where it
imparts a red tinge color, the exudates are called
serosanguineous exudates.
Microscopically,
fibrin is viewed as solid clumps of long delicate eosinophilic strands.
– these exudates are characterized by
the production of pus (suppuration) which is a thick creamy fluid composed of a
large number of viable and dead polymorphs.
Purulent or Suppurative exudates
The exudates are fluid because of
the hydrolytic enzymes produced and released by the leucocytes.
In avian
species, since their heterophils lack the hydrolytic enzymes, purulent exudates
are semi-solid compared to the fluid nature of the exudates seen in mammals.