Acute And Chronic Inflammatiin

Question 1

Two types of inflammation

Answer 1

Inflammation may be of two types, acute and chronic.

Question 2

Describe acute inflammation

Answer 2

The initial, rapid response to infections and tissue damage is called acute
inflammation

Question 3

Describe Chronic inflammation

Answer 3

if the initial response fails to clear the stimulus, the reaction progresses to a
protracted type of inflammation that is called chronic inflammation

Question 4

5 CAUSES OF INFLAMMATION

Answer 4

Infections- bacteria, viruses, fungi
• Immune reaction-hypersensitivity
• Foreign bodies
• Tissue necrosis

Question 5

Describe the 3 major components of acute inflammation

Answer 5

Dilation of small vessels, leading to an increase in blood flow,
• Increased permeability of the microvasculature, enabling plasma proteins and
leukocytes to leave the circulation, and
• Emigration of the leukocytes from the microcirculation, their accumulation in the focus
of injury, and their activation to eliminate the offending agent

Question 6

Describe the 3 REACTIONS OF BLOOD VESSELS IN ACUTE
INFLAMMATION

Answer 6

An exudate is an extravascular fluid that has a high protein concentration and contains cellular
debris. Its presence implies that there is an increase in the permeability of small blood vessels,
typically during an inflammatory reaction.
• In contrast, a transudate is a fluid with low protein content, little or no cellular material, and low
specific gravity. It is essentially an ultrafiltrate of blood plasma that is produced as a result of osmotic
or hydrostatic imbalance across vessels with normal vascular permeability
• Oedema denotes an excess of fluid in the interstitial tissue or serous cavities; it can be either an
exudate or a transudate.

Question 7

PHAGOCYTOSIS AND CLEARANCE OF
THE OFFENDING AGENT
• Phagocytosis involves three sequential steps: describe them

Answer 7

• Recognition and attachment of the particle to be ingested by the leukocyte
• Engulfment, with subsequent formation of a phagocytic vacuole
• Killing or degradation of the ingested material

Question 8

What is the complement system

Answer 8

The complement system is a collection of soluble proteins and their membrane
receptors that function mainly in host defense against microbes and in pathologic
inflammatory reactions

Question 9

• List the morphology patterns of acute inflammation

Answer 9

FIBRINOUS INFLAMMATIO
PURULENT INFLAMMATION
Ulcer

Question 10

3 OUTCOMES OF ACUTE
INFLAMMATION

Answer 10

• Complete resolution
• Healing by connective tissue replacement (scarring, or fibrosis).
• Progression of the response to chronic inflammation.

Question 11

What is Chronic inflammation

Answer 11

• Chronic inflammation is a response of prolonged duration (weeks or months) in
which inflammation, tissue injury, and attempts at repair coexist, in varying
combinations.
• It may follow acute inflammation, as described earlier, or may begin insidiously,
as a smoldering,
• Sometimes progressive process without any signs of a preceding acute reaction.

Question 12

3 CAUSES OF CHRONIC INFLAMMATION

Answer 12

Persistent infections
• Hypersensitivity diseases.
• Prolonged exposure to potentially toxic agents, either exogenous or endogenous.

Question 13

Describe CELLS AND MEDIATORS OF CHRONIC
INFLAMMATION

Answer 13

• The dominant cells in most chronic inflammatory reactions are macrophages,
which contribute to the reaction by secreting cytokines and growth factors that act
on various cells, by destroying foreign invaders and tissues, and by activating
other cells, notably T lymphocytes.

Question 14

Name the two major pathways of macrophage activation

Answer 14

classical and
alternative

Question 15

Describe the role of lymphocytes

Answer 15

Microbes and other environmental antigens activate T and B lymphocytes, which amplify and
propagate chronic inflammation
• By virtue of their ability to secrete cytokines, CD4+ T lymphocytes promote inflammation and
influence the nature of the inflammatory reactionMicrobes and other environmental antigens activate T and B lymphocytes, which amplify and
propagate chronic inflammation
• By virtue of their ability to secrete cytokines, CD4+ T lymphocytes promote inflammation and
influence the nature of the inflammatory reaction

Question 16

What is GRANULOMATOUS INFLAMMATION

Answer 16

Granulomatous inflammation is a form of chronic inflammation characterized by collections
of activated macrophages, often with T lymphocytes, and sometimes associated with
central necrosis

Question 17

two types of granulomas

Answer 17

Immune granulomas are caused by a variety of agents that are capable of inducing a
persistent T cell–mediated immune response.
• This type of immune response produces granulomas usually when the inciting agent
cannot be readily eliminated, such as a persistent microbe or a self antigen.
• In such responses, macrophages activate T cells to produce cytokines, such as IL-2,
which activates other T cells, perpetuating the response, and IFN-γ, which activates
the macrophages.

Foreign body granulomas are seen in response to relatively inert foreign bodies,
in the absence of T cell– mediated immune responses.
• Typically, foreign body granulomas form around materials such as talc (associated
with intravenous drug abuse), sutures, or other fibers that are large enough to
preclude phagocytosis by a macrophage but are not immunogenic.
• Epithelioid cells and giant cells are apposed to the surface of the foreign body.
• The foreign material can usually be identified in the center of the granuloma,
particularly if viewed with polarized light, in which it may appear refractile.

Question 18

4 systemic effects ipof inflammation

Answer 18

The acute-phase response consists of several clinical and pathologic changes:
• Fever
• Acute-phase proteins are plasma proteins, mostly synthesized in the liver, whose
plasma concentrations may increase several hundred-fold as part of the
response to inflammatory stimuli. E.g CRP
• Leukocytosis

Question 19

2 types of tissue repair reactions

Answer 19

Regeneration
Scarring

Question 20

Repair by regeneration

Answer 20

Different tissues consist of continuously dividing cells (epithelia, hematopoietic tissues),
normally quiescent cells that are capable of proliferation (most parenchymal organs),
and nondividing cells (neurons, skeletal and cardiac muscle).
• The regenerative capacity of a tissue depends on the proliferative potential of its
constituent cells.
• Cell proliferation is controlled by the cell cycle, and is stimulated by growth factors and
interactions of cells with the extracellular matrix.
• Regeneration of the liver is a classic example of repair by regeneration. It is triggered by
cytokines and growth factors produced in response to loss of liver mass and inflammation. In
different situations, regeneration may occur by proliferation of surviving hepatocytes or
repopulation from progenitor cells.

Question 21

Repair by scarring

Answer 21

• If repair cannot be accomplished by regeneration alone, it occurs by replacement
of the injured cells with connective tissue, leading to the formation of a scar, or by
a combination of regeneration of some residual cells and scar formation.
• The term scar is most often used in connection to wound healing in the skin, but
also may be used to describe the replacement of parenchymal cells in any tissue
by collagen, as in the heart after myocardial infarction.

Question 22

• The main steps in repair by scarring are

Answer 22

clot formation,
• inflammation,
• angiogenesis
• formation of granulation tissue, migration and proliferation of fibroblasts, collagen synthesis, and
• connective tissue remodeling.

Question 23

6 FACTORS THAT IMPAIR TISSUE REPAIR

Answer 23

• Diabetes
• Nutritional status
• Glucocorticoids (steroids)
• Mechanical factors such as increased local pressure or torsion may
cause wounds to pull apart (dehisce).
• Poor perfusion, resulting either from arteriosclerosis
• Foreign bodies such as fragments of steel, glass, or even bone impede
healing

Question 24

4 CLINICAL EXAMPLES OF ABNORMAL WOUND
HEALING
AND SCARRING

Answer 24

•Venous leg ulcers
•Arterial ulcers
•Pressure sores
• Diabetic ulcers

Question 25

Describe EXCESSIVE SCARRING

Answer 25

• Excessive formation of the components of the repair process can give rise to
hypertrophic scars and keloids. The accumulation of excessive amounts of
collagen may result in a raised scar known as a hypertrophic scar.

Question 26

Describe EXUBERANT GRANULATION

Answer 26

Exuberant granulation is another deviation in wound healing characterized by the
formation of excessive amounts of granulation tissue, which protrudes above the level of
the surrounding skin and blocks reepithelialisation (this process has been called, with
more literary fervor, proud flesh).
• Excessive granulation must be removed by cautery or surgical excision to permit
restoration of epithelial continuity.
• Rarely, incisional scars or traumatic injuries may be followed by exuberant proliferation
of fibroblasts and other connective tissue elements that may, in fact, recur after excision.
• Called desmoids, or aggressive fibromatoses, these neoplasms lie at the gray zone of
benign and malignant low-grade tumours