UNIT 4 : INFLAMMATION
Outcomes
• Describe the components and process of the
inflammatory response.
• Differentiate between acute and chronic
inflammation.
Please watch the video as this will help you understand the
cells involved in the inflammatory process better as well
as why the cardinal signs occur
The Inflammatory Response
https://www.youtube.com/watch?v=qCpWXPSMBIY
AND
Clinical features of inflammation
https://www.youtube.com/watch?v=Kpx56iDvCdU
Differentiate between
Infection
• Is present when pathogenic micro-organisms have established
themselves in the tissues of some part(s) of the body and are
able to survive and reproduce themselves therein
Inflammation
• Mechanism by which the body deals with an injury or insult
• Process is characterized by release of inflammatory mediators
and movement of fluid and leukocytes from the vasculature
into the extravascular tissue
Without inflammation, infections would go unchecked, wounds would
not heal and injured tissues might remain permanent festering sores
CAUSES OF INFLAMMATION
• Infections (bacterial; viral ; fungal and parasitic) and
microbial toxins – can range from mild to severe inflammation
• Tissue necrosis due to ischaemia, trauma, physical and
chemical injury (e.g. burns, frostbite, irradiation and
environmental chemicals)
• Foreign bodies(splinters, dirt, sutures) or endogenous
substances( urate crystals ; cholesterol crystals) and lipids
(obesity associated metabolic syndrome)
• Immune reactions (allergies or auto-immune diseases)
Cells of inflammation i.e endothelial cells;
platelets, leukocytes
• Endothelial cells
- Lines the blood vessels and form capillaries
- Separates intravascular and extravascular spaces
- Produce agents that maintain vessel patency + vasodilators +
vasoconstrictors
- In the inflammatory process – provides a selective permeability
barrier to exogenous and endogenous stimuli + regulates
leukocyte extravasation(DIAPEDESIS) + regulation of immune
responses + regulate immune cell proliferation
- Part of repair process- produces growth factors
• Platelets
- Plays a role in homeostasis
- Release inflammatory mediators that increase vascular
permeability ; alters chemotactic, adhesive and proteolytic
properties of endothelial cells
- Over 300 proteins can be released when a platelet is
activated
Leukocytes
Granulocytes
Agranulocytes
Neutrophils
Monocytes
Eosinophils
Lymphocytes
Basophils
GRANULOCYTES
Neutrophils
Eosinophils
Basophils/Mast cells
Most numerous- first to
appear at site of
inflammation
Accounts for 2-3%- appears
much later than neutrophilsslow mobility
Accounts for <1%
Short life span
Longer life span than
neutrophils
Contains a protein that is
highly toxic to large parasitic
worms that cannot be
phagocytosed
Scavenger cells – contains
enzymes that degrade and
engulf microbes and dead
tissue
Contain pathways for H2O2
and NO that aid in
destruction of pathogens
Important in allergic
reactions and collagen
diseases– releases chemical
mediators
Most prominent in allergic
reactions- mediated by IgE
Prevalent along the mucosal
surfaces of the GIT tract;
lung and dermis of the skin
Rich in histamine(triggers
inflammation) and
heparin(anti-coagulant)
Stimulate synthesis of
cytokines and chemokines
AGRANULOCYTES
Monocytes (Macrophages)
Lymphocytes
Constitutes 3-8% of WBC – largest of
circulating leukocytes
Smallest of the leukocytes –
predominant in lymphatic system than
in blood
Longer life span than granulocytes – assists in
destroying causative agent, resolve
inflammatory process, contributes to healing
process
NB in maintain chronic inflammation
Linked to inflammatory conditions such as
atherosclerosis
Produces vasoconstrictive mediators;
inflammatory cytokines and growth factors
that promote regeneration of tissues
Capable of phagocytosis and bacterial killing
Participates in immune and non
immune mediated inflammation
caused by infectious agents
Production of anti-bodies directed
against persistent antigens
The steps of the inflammatory process can be remembered
by the cardinal signs and the 5 ”R’s”
5R’s = sequential steps of the inflammatory process:• RECOGNITION - Offending agent in extravascular tissues is
recognized by host cells and molecules
• RECRUITMENT- Leukocytes and plasma proteins located to
area of offending agent
• REMOVAL- Leukocytes and proteins activated to destroy and
eliminate offending agent
• REGULATION- Reaction is controlled and terminated
• REPAIR- The damaged tissue is repaired
Unit 4 Task 3
FOR DISCUSSION IN THE NEXT
LECTURE PERIOD!!!!!!!
1. Differentiate between ACUTE and CHRONIC inflammation
2. Briefly discuss the stages of acute inflammation…..
REFER TO THE PRESCRIBED TEXTBOOK!!!!!!
3. Differentiate between a transudate and an exudate and
state the functions of an exudate
4. Discuss the manifestations/sequelae of acute
inflammation
REFERENCES
• Porth, C.M. (2015). Essentials of Pathophysiology. 4th
Ed. Wolters Kluwer.
• Kumar,R., Abbas, A. & Aster,E. (2015): Pathologic Basis of
Disease. 9th Ed., Elsevier
• Loveday, J. (1994): Davies’ Medical Terminology: A guide
to current usage. 5th Ed., Butterworth Heineman, Oxford