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Batch 07- Immunology A.02 - BEd 72018172

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THE REASONS FOR INFLAMMATORY RESPONSES
Figure - Inflammatory responses
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The immune system is our body's natural defense against foreign invaders such as environmental
toxins, pollutants, bacteria, germs and viruses. When tissue injury like trauma, chemicals or heat
occurs multiple series of events activates in order to remove the damaged tissue, antigens. For
healing it undergoes nonspecific, first immune response known as inflammatory response which
entitled for second line defense mechanism. As a result inflamed area characterized four common
signs like redness, heat, swelling and pain which initiated within hours of wounding undergoing
local inflammatory response.
Chemical alarm signals released histamine by mast cells, prostaglandins and cytokines like
C5a and Tumor Necrosis Factor-α causing vasodilation that increased vascular diameter and
make more permeable. Enlarged capillaries enhance blood flow slowing the speed causing the
skin redden which known as hyperemia. Vasodilation occurs providing lots of energy (oxygen) to
replace or repair the damaged or injured tissue cells to assist healing process. Moreover wounded
area may acetic if carbondioxide don’t move from wounded site that generated in anabolic repair
process. Likewise vasodilation reasoning redness keep the optimum p H level for healing.
The inflammatory response is accompanied by an acute phase response. One manifestation of this
response is an elevation of body temperature. Vasodilation divert lots of warm blood from the
core of the body to the body surface accounting for heat. Moreover macrophage with a Toll-like
Receptor on its surface binds to a pathogen-associated molecular patterns and cytokine called
interleukin-1 (IL-1) is released to carry the blood to the brain making neurons in the hypothalamus
to raise the body’s temperature which enhance phagocytosis, speed chemical reactions, accelerate
tissue repair, impedes the growth of some microorganisms and cause the liver and spleen to store
iron reducing bacterial growth.
Meanwhile various types of white blood cells migrate from the bloodstream into damaged tissues
called as extravasation. Monocytes can differentiate into dendritic cells and macrophages which
are able to devour many pathogens and still survive. Activated macrophages discharge cytokines,
which pass signals by way of the blood to the red bone marrow where they stimulate the
production and release of white blood cells.
Increased capillary permeability initially promotes the migration of phagocytic neutrophils from
the blood to the tissues in extracellular fluid, where the neutrophils can ingest and degrade
pathogens. The pus associated with some infections is a mixture of dead or dying pathogens, tissue
cells and neutrophils and an exudate of fluid such as pus, oputum from the plasma increasing the
amount of tissue fluid account swelling. Since tissue fluid contain more nutrients like amino acids
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that need to form cell organs, phospholipids for cell membrane formation, Vitamin C for collagen
formation and glucose for energy generation assists healing process.
Various chemicals released by damaged cells like Leukotriene, bradykinin and prostaglandins
induce pain by stimulating free nerve endings which contain pain receptors known as nociceptors
that occurs because of the pressure put by swelling. They release mediators like histamine,
complements and kinins, causing the sensation of pain easing to generate nerve impulse
accounting for pain and alerts to rest particular injured body part.
Finally the clotting system activated by fluid, antimicrobial proteins such as fibrinogen and
platelets move from the blood to the broken capillary, to prevent from further blood loss and
making the area seal.
References :
1. Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, J. B. R. (2017)
Campbell Biology. Eleventh e. Pearson Education, Inc., pg 955
2. Mader, S. S., Windelspecht, M., Carlson, J., Guest, G. (2016) Biology, 12th edition. McGraw
Hill Education., pg 625-628
3. Mason, K. A., Losos, Jonathan B, Singer, Susan R, Raven, Peter H (2011) Biology. Nineth
edi. The McGrow-Hill Companies., pg 1058-1060
4. Neutral
Academy,
The
inflammatory
response,
22
May,
2019,
https://www.youtube.com/watch?v=Fbzb75HA9M8
5. Dr. Campbell, J. The tissue response to
inflammation, 26 November, 2015,
https://youtu.be/NBwAT1w71V0
6. David W. Woodruff (2014), Chamberiain College of Nursing, Innate immunity: inflammation
and wound healing, https://youtu.be/Md-EGWfLGys
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