Lecture 8 – Inflammation
- Reaction of the microcirculation (venules, capillaries, arterioles react to damage or pathogen)
characterized by movement of fluid and leukocytes from blood into extravascular tissues.
- Protective response to cell injury, intended to remove the cause of injury along with any
necrotic cells and tissues.
- Lasts from a few minutes to a few days
- Minor cuts, bites, etc.
- Dealing with the presence of dead neutrophils
- Use neutrophils because they are easier and cheaper (energetically) to produce
- Immediate response to injury
- Main focus is rapid delivery of leukocytes to affected tissues
- Three major components:
1) Change in caliber of blood vessels (open it up; become wider)
2) Structural changes in endothelium (allows cells to exit; typical endothelium not
easy to get across)
3) Extravasation of leukocytes – escape of blood or lymph from their proper vessels
into surrounding tissues
1) Flow and Caliber
a) Transient vasoconstriction (probably serotonin released) of arterioles at site of
injury—sudden stop of blood flow to region
b) Vasodilation of pre-capillary arterioles
Caused by Nitric Oxide, histamine, interleukins
Opens up microvascular beds
Influx of blood ―calor‖ and ―rubor‖
Slows down laminar (blood) flow leukocytes marginate, make contact
o Cell surface molecules produced by endothelial cells will give signal
to leukocytes for where site of infection is and where inflammation
2) Vascular Permeability
- Lumen leaks out of blood vessel
- H 2 leaves vessel and enters CT
- How does leakage occur?
Endothelial cell contraction – pull away from e