Inflammation

Inflammation: reaction of vascularized living tissue to local injury, irritants or agents.

• associated with the repair process
• protective response

]]Tissue Injury]]

Reversible: mild or moderate injury (leads to inflammation or degeneration)

Irreversible: severe injury (leads to necrosis)

]]Types of Inflammatory Response]]

• Acute inflammation
• Chronic inflammation

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]]Two Major Components of Inflammation]]

1. Vascular reaction
2. Cellular response

]]Benefits of Inflammation]]

1. Contain and isolate injury
2. Destroy invading microorganisms and inactive toxins
3. Prepare tissue for healing and repair

]]Causes of Inflammation]]

Physical agents:

• excessive heat or cold
• irradiation

Tissue necrosis:

• ischemia
• trauma
• toxins

Foreign bodies:

• splinters
• dirt
• suture
• prosthetic device
• urate crystals (gout)
• cholesterol esters

Chemical agents:

• concentrated acids and alkalis

Infection: (most common cause)

• bacteria and their toxins
• fungi
• parasites

Immunological:

• due to: antigen - antibody reactions

]]Mediators of Defense]]

• phagocytic leukocytes
• antibodies
• complement proteins

]]Typical Inflammatory reaction]]

1. recognition of injurious agent
2. recruitment of leukocytes and plasma proteins
3. removal of the agent
4. regulation of the response
5. repair

]]Major participants]]

1. blood vessels
2. leukocytes

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]]Harmful Consequences of Inflammation]]

Local tissue damage and its associated signs and symptoms are self-limited and resolve as the inflammation diminishes, leaving little or no permanent damage.

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Inflammation becomes the cause of the diseases when it:

• is misdirected (autoimmune diseases)
• occurs against normally harmless environmental substances (e.g. allergies)
• inadequately controlled

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]]Cardinal Signs of Inflammation]]

1. Hotness
   • due to: increased blood flow
2. Redness:
   • due to: vasodilation and increased blood flow
3. Swelling:
   • due to: exudate
4. Pain:
   • due to: irritation of nerve endings by metabolites
5. Loss of function:
   • due to: pain and tissue damage

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