What is inflammation?

What is inflammation

Inflammation is the body's response to injury, infection, or irritation, characterized by redness, swelling, heat, pain, and sometimes loss of function. It is a complex physiological process involving the immune system that aims to remove harmful stimuli and initiate the healing process.

Types of inflammation

There are two main types of inflammation:

1. Acute Inflammation: Acute inflammation is a short-term, immediate response to tissue injury or infection. It is characterized by redness, swelling, heat, pain, and loss of function in the affected area. Acute inflammation is typically a protective response aimed at eliminating the harmful agent and initiating tissue repair.

2. Chronic Inflammation: Chronic inflammation is a prolonged and persistent inflammatory response that can last for weeks, months, or even years. It is often associated with conditions such as autoimmune diseases, persistent infections, or prolonged exposure to irritants. Chronic inflammation can lead to tissue damage and is characterized by the infiltration of immune cells, tissue destruction, and attempts at tissue repair.

Causes of inflammation 

Causes of Inflammation:

1. Infection

2. Injury or trauma

3. Autoimmune disorders

4. Allergic reactions

5. Irritants or toxins

6. Tissue damage or necrosis

7. Chronic diseases

8. Radiation exposure

9. Foreign bodies or implants

10. Metabolic disorders

Cardinal sign of inflammation 

The cardinal signs of inflammation are:

1. Redness (rubor)

2. Swelling (tumor)

3. Heat (calor)

4. Pain (dolor)

5. Loss of function (functio laesa)

Vascular and cellular events of inflammation 

Vascular events of inflammation:

1. Vasodilation: Blood vessels in the affected area widen, leading to increased blood flow, redness, and warmth.

2. Increased vascular permeability: The blood vessel walls become more permeable, allowing fluid, proteins, and immune cells to move from the blood vessels into the surrounding tissues, causing swelling or edema.

3. Activation of endothelial cells: The endothelial cells lining the blood vessels express adhesion molecules and secrete inflammatory mediators, facilitating the recruitment of immune cells to the site of inflammation.

Cellular events of inflammation:

1. Leukocyte recruitment: White blood cells, particularly neutrophils, are attracted to the site of inflammation by chemotactic factors released by injured tissues and activated endothelial cells.

2. Adhesion and margination: Leukocytes adhere to the endothelial cells of blood vessels and marginate along the vessel walls, preparing for their migration into the inflamed tissue.

3. Leukocyte migration: Leukocytes squeeze through the gaps between endothelial cells, migrating from the blood vessels into the tissues, guided by chemotactic signals.

4. Phagocytosis: Neutrophils and macrophages engulf and eliminate pathogens, debris, and damaged cells through phagocytosis, contributing to the resolution of inflammation.

These vascular and cellular events are essential components of the inflammatory response and play a crucial role in eliminating harmful stimuli and initiating tissue repair.

Gross structure and microscopic structure of inflammation

Gross Structure of Acute Inflammation:

1. Redness (rubor): Increased blood flow to the area.

2. Swelling (tumor): Accumulation of fluid and cells.

3. Heat (calor): Increased temperature due to increased blood flow.

4. Pain (dolor): Sensory nerve stimulation.

5. Loss of function (functio laesa): Impaired function due to inflammation.

Microscopy of Acute Inflammation:

1. Neutrophil infiltration: Presence of neutrophils, the predominant inflammatory cells.

2. Vasodilation: Dilated blood vessels and increased blood flow.

3. Increased vascular permeability: Leakage of fluid and proteins into the tissue.

4. Tissue edema: Swelling due to fluid accumulation.

5. Tissue damage: Disruption of normal tissue architecture.

Chemical Mediators of acute inflammation

Chemical Mediators of Inflammation:

1. Histamine: Released by mast cells, causes vasodilation and increased vascular permeability.

2. Prostaglandins: Promote vasodilation, pain, and fever.

3. Leukotrienes: Induce chemotaxis and increased vascular permeability.

4. Cytokines: Regulate immune response and inflammation.

5. Bradykinin: Induces vasodilation, pain, and increased vascular permeability.

6. Complement system: Enhances inflammation and opsonization.

7. Nitric oxide: Mediates vasodilation and regulates immune response.

8. Serotonin: Contributes to vasodilation and platelet aggregation.

9. Reactive oxygen species: Promote tissue damage and inflammation.

10. Chemokines: Attract immune cells to the site of inflammation.

Inflammatory cells of inflammation

 

Inflammatory Cells in Inflammation:

1. Neutrophils: Phagocytic cells that migrate to the site of inflammation early on.

2. Macrophages: Phagocytic cells involved in engulfing and clearing debris and pathogens.

3. Lymphocytes: Play a role in adaptive immune response and can amplify or regulate inflammation.

4. Eosinophils: Involved in allergic and parasitic responses.

5. Mast cells: Release histamine and other mediators, initiating and amplifying inflammation.

6. Basophils: Similar to mast cells, release inflammatory mediators.

7. Monocytes: Precursors to macrophages, migrate to the site of inflammation and differentiate into tissue-specific macrophages.

https://chat.whatsapp.com/D8ioqtYVOd01sFUevmQTMB