9.21 Injury, Inflammation, Healing 7 Flashcards
steps of vascular alterations after injury
- initial vasoconstriction
- vasodilation
- clot formation (if vessel disruption)
- transudation (if vessel not disrupted)
initial vasoconstriction
- chemically mediated
- 5-10 mins after injury
Initial vasoconstriction is chemically mediated by this hormone
norepinephrine
Why does the body undergo initial vasoconstriction?
to stop bleeding
vasodilation is chemically mediated by these
- histamine
- Hageman factor
- bradykinin
- prostaglandins
- complement fractions
When does vasodilation occur?
- after initial vasoconstriction
- 1 hour after injury
If the vessel is disrupted, what happens after vasodilation?
aggregation of platelets forms a clot
Transudation: vessel not disrupted
- NEURALLY mediated arterial constriction is followed by vasodilation
- protein-poor fluid forced into injured tissue
transudate composition
- dissolved electrolytes
- water
exudate composition
- plasma proteins
- lipids
- cellular debris (cloudy)
pus composition
- neutrophils
- digested tissue
- fluid
- bacteria
What are the types of transudate?
- transudate
- exudate
- pus
- blood
- effusion
What is effusion?
swelling within a cavity
types of effusion
- joint effusion
- pleural effusion
- ascites
- peritoneal effusion
ascites
abdominal effusion
Any time there’s this, it is called transudation
leakage into interstitial tissue
Transudation is fine as long as we don’t continue to lose these
proteins
How do you distinguish hemarthrosis from swelling?
- surrounding the joint
- warm
- fluctuant
fluctuant
push out on one side, the other side balloons out
How does exudation affect blood flow?
leads to stasis (slowing or cessation of flow in vessels)
Leukocytes accumulate here, adhere, here, then migrate here
- accumulate at injury site
- adhere to endothelial cells
- migrate to interstitial space
Of the leukocytes, these predominate
neutrophils
What do neutrophils release?
- lactoferrin (bacteriostatic)
- defensin (cytotoxic to other microbes)
neutrophil life cycle
- usu die within 24 hours
- can persist in certain infections
