Why Inflammation occurs in the body?
Introduction
Just take an example, an infection succeeds in invading the body and reaches the tissue spaces. Would you want to leave that invader, or kill? Yes, 100% you would want to eliminate that invader. Then it depends on you how you eliminate that invader. The body also wants the same to eliminate that but it involves some processes that is called Inflammation.
What is Inflammation?
When a tissue injury occurs, it dramatically leads to the number of changes that may include an increase in the production of WBCs or releasing chemicals that help in the chemotaxis of neutrophils or macrophages.
How is Inflammation Characterized?
There are number of changes that are the characteristics of inflammation includes:
- The vasodilation of local vessels occur.
- Increase in the permeability of vessels that leads to the leakage of fluids causing edema.
- Fluid clotting in the Interstitial spaces.
- Migration of Granulocytes and Monocytes towards the inflamed area.
- Due to the leakage of leads, it leads to the swelling of that area.
What is the Walling-Off process?
Inflammation aims to the walling-off the damaged tissues from the healthy tissues so that their should not be the chance of spreading, that's why walling-off occurs that delay the spread of infection.
Response of Neutrophil and Macrophage
When the injury occurs, a number of defense lines are present that give the response to the infection. These defense lines are nothing but the responses of neutrophils and macrophages.
First line of defense
Whenever the body is attacked by infection, the tissue macrophages are ones that ultimately starts phagocytosis of that infection. These macrophages may be the histiocytes, alveolar macrophages, kupffer cells, lymph node macrophages or the macrophages of spleen and bone marrow.
Second line of defense
As the injury occur, that injured part of tissue secretes number of chemicals like Tissue necrosis factor (TNF) or Interleukin-1 (IL-1). These chemicals cause the expression of adhesion molecules or iCAMs, that leads to the imagination of neutrophils and ultimately the diapedesis occurs and neutrophils enter in the tissue spaces. Then the chemicals release by injured tissue leads to the chemotaxis of neutrophils.
Acute increase of neutrophils in the blood occurs that is termed as Neutrophillia, that occurs due to the products of inflammation that enters the blood, then reach the bone marrow where they stimulates the production of neutrophils.
Third line of defense
After 2nd line of defense, the monocytes that are in circulation, enter the tissue spaces and leads to conversion of monocyte to macrophage, but not mature coz it needs almost 8 hours to become tissue macrophage of full capacity, that then dominate the process after several days or several weeks.
These macrophages also have an important role in antibody formation.
Fourth line of defense
When the increase in the production of granulocytes and monocytes occurs, it means that now the fourth line of defense has started. If the stimulation of production continuous, then last for long time and produces lot of cells.
Feedback Control of Both Responses
Feedback control is done by five major factors that are given below:
- Interleukin-1
- Tissue Necrotic Factor
- Granulocyte Monocyte Colony Stimulating Factor
- Granulocyte Colony Stimulating Factor
- Monocyte Colony Stimulating Factor
Last three, Granulocyte Monocyte Colony Stimulating Factor, Granulocyte Colony Stimulating Factor and Monocyte Colony Stimulating Factor stimulates the production of WBCs.
Pus Formation
After the engulfment of infection, digestion starts and leads to the death of all neutrophils or most macrophages. Cavity containing different amounts of necrotic tissue, dead neutrophils, dead macrophages and tissue fluid. The whole mixture is called Pus.
Conclusion
In the end, everyone know that Inflammation is good if its occurring physiologically, otherwise pathologically leads to different consequences.
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