Inflammation pathology notes – Short and easy revision notes

Inflammation is define as the local response of living tissues to injury from any agent. It is a body defence reaction in order to eliminate or limit this spread of injurious agent.

Generally we see inflammation as a harmful reaction but actually it is a protective response that is essential for our survival.

Causes of inflammation

Infective agents – bacteria, virus, toxins, fungi etc…

Immunological agents – cell mediated and antigen antibody reaction.

Physical agents – heat, cold, radiation, chemical trauma etc…

Chemical agents – organic and inorganic poisons.

Inert material – Foreign bodies.

Signs of inflammation

• Redness

• Swelling

• Heat

• Pain

Inflammatory reaction fundamental properties

1. Components of inflammatory responses

The major participants in inflammation in tissues are blood vessels and leukocytes.

• Blood vessels – blood vessels dialed to slow down blood flow
  • Slowing of blood flow helps blood to enter the site of infection and increase permeability.

• Leukocytes – leukocytes are activated, which has acquire the ability to ingest and destroy microbes and dead cells.

2. Harmful consequences of inflammation

• Local tissue damage
• Pain
• Functional impairment
• Leaving little permanent damage

3. Local and systematic inflammation

Local inflammation – which type of inflammation is localized in a particular area and do not respect to other areas.

Systematic inflammation – In this type of inflammation there is spread of infection through blood is known as estematic inflamation it is also called sepsis.

4. Mediators of inflammation

• Vascular and cellular reactions
• Microbes, necrotic cells and hypoxia.

5. Termination of inflammation

Inflammation is terminated when the offending agent becomes limited.

The inflammation reaction resolves completely when the mediators are broken down.

Sequential steps of inflammatory reaction

Step 1 – The offending agent which is located in extravascular tissue is recognised by host cells.

Step 2 – Leukocytes and plasma proteins are taken from circulation to the site where the offending agent is located.

Step 3 – The leukocytes and proteins are activated and work together to destroy and eliminate the offending agent.

Step 4 – The reaction is controlled and terminated after the destruction and elimination of offending agents.

Step 5 – The damaged tissue is then repaired.

Types of inflammation

Acute inflammation – it is a type of information which has rapid response to infections and tissue damage. It typically develops within minutes or hours and last for several hours or few days.

Chronic inflammation – it is a type of inflammation which persist for a longer duration.

Summary

Inflammation is a beneficial host response to foreign invaders but it may also cause tissue damage.

Main component of inflammation are vascular reaction and a cellular response both are activated by mediators that are derived from plasma protein and various cells.