1. Inflammation
Taylor, ch 27

2. Objectives p. 4 Inflammation and Infection objectives are intertwined.
Inflammation is the concept and appendicitis is the exemplar (best example) of inflammation.

3. Inflammation: What it is and What it isn’t.
The body’s cellular response to injury, infection, or irritation.
Mechanism is the same regardless of injuring agent.
Always present with infection.
It is not infection. Infection is not always present with inflammation.

4. Inflammatory Response
Intensity depends on extent and severity of injury & body’s ability to react
Sequential:
Neutralizes & dilutes inflammatory agent
Removes necrotic materials
Establishes an environment suitable for healing and repair

5. Causes of Inflammatory Response
Heat—burn injury
Radiation—sunburn, radiation tx
Trauma
Allergens—sinuses; anaphylactic shock
Infection

6. Steps of Inflammatory Response
Vascular response
Cellular response
Formation of exudate
Healing

7. Vascular Response Cell injury local vasoconstriction
release of kinins, antihistamines, prostaglandins
local vasodilation and hyperemia
increased capillary pressure and permeability
fluid exudate from capillaries to tissue spaces leading to edema

8. Vascular Response cont’d
Fluid exudate contains fibrinogen
Fibrinogen changes to fibrin
Fibrin and platelets make clot
Clot traps bacteria to prevent spread

9. Cellular Response
WBCs—specifically neutrophils and monocytes—migrate thru capillary walls to site of injury. This migration is called chemotaxis.
Neutrophils and monocytes (which change to macrophages) perform phagocytosis, cleaning up bacteria and dead cells.

10. Cellular Response cont’d
Other cells that may be released:
Eosinophils—allergic responses
Lymphocytes—help develop immunity
Basophils—carry histamine and heparin

11. Cellular Response: Chemical Mediators
Mediators released that play a role in inflammatory response and cell lysis:
Histamine
Serotonin
Complement system
Prostaglandins
Kinins

12. Formation of Exudate
Formed when fluid leaks from capillaries into tissue spaces
Made up of serous fluid, cells, chemical mediators
Sometimes confused with infection in an open wound because it may look milky white, yellowish, or pale green, but it has no odor if infection is not present.

13. Manifestations of Inflammation
Localized response (redness, pain, swelling, etc) and systemic response (increased TPR, malaise, nausea, anorexia, etc) are the same as in the infectious process (see Infection Concept Lecture)
With a high degree of inflammation, and when infection is present, WBCs rise

14. Types of Inflammation
Acute—healing occurs 2-3 weeks; primarily neutrophils involved
Subacute—healing occurs same way, but takes longer
Chronic—may last for years; injurious agent persists or repeats injury to site; primarily lymphocytes and macrophages (monocytes) involved.

15. Healing Process
Regeneration—replacement of lost cells and tissues with cells of same type
Repair—replacement of lost cells with connective tissue (scar)

16. Healing Process cont’d
Regenerative cells:
Skin
Bone and bone marrow
Mucous membranes
Spleen
Liver
Kidney
Pancreas

17. Healing Process cont’d
Non-regenerative cells:
Neurons—replaced by glial cells, new neurons may be produced by stem cells
Skeletal and cardiac—repaired with scar tissue

18. Acute Inflammation Video7