Lecture 3: Hemodynamics Flashcards
Artery or vein
artery
Artery or vein
vein
What is edema
Abnormal accumulation of fluid in the interstitium and body cavities
What are the 4 causes of edema
- Increased microvascular permeability
- Increased vascular hydrostatic pressure
- Decreased intravascular oncotic pressure
- Decreased lymphatic drainage
What are some causes of increase microvascular permeability
Inflammation, neovascularization, anaphylaxis, toxin, clotting abnormalities
What are some causes for increased vascular hydrostatic pressure
Portal hypertension, pulmonary hypertension, localized venous obstruction
What are some causes of decreased intravascular osmotic pressure
Hypoalbumemia, excessive albumin loss
What are some causes for decreased lymphatic drainage
Lymphatic obstruction or compression, lymphatic aphasia or hypoplasia, interstitial lymphangiectasia, lymphangitis, spirotrichosis
What are 2 major causes of non-inflammatory edema and transudate
- Hepatic disease- hypoalbumemia, portal hypertension—> increase hydrostatic pressure
- Heart failure- LHF- pulmonary edema, RHF- ascites—> increase hydrostatic presure
How does the body attempt to compensate for hepatic failure and heart failure resulting in decreased CO
Activate RAAS system—> increase Na+ and H20 retention, AII activates anti-diuretic hormone- retain water
Ends up increasing hydrostatic pressure
What is hyperemia and what are some reasons why
Ateriolar dilation (erythema in skin) due to inflammation, physical activity, increase BF to GI after meal, physiological mechanism of dissipate heat
What is congestion (BF and perfusion) and some reasons why
Impaired/decreased outflow due to CHF, local venous obstruction, displacement of organ
What is hemostasis
Physiological response to vascular damage and stop bleeding- normal to prevent blood loss
What is thrombosis
Inappropriate activation of hemostatic processes in blood vessels, occurs without trauma
What is Virchow’s Triad
3 factors that contribute to hemostasis and thrombosis
1. Endothelial injury
2. Alterations in blood flow
3. Blood hypercoaguability
What are the steps in the hemostatic process
- Primary hemostasis- vasoconstriction and platelet aggregation to form platelet plug at site of damage- uses von willebrand factor to help adhere platelets to endothelium
- Secondary hemostasis- coagulation to form a mesh work of fibrin- uses tissue factor because once activated upon endothelial injury activates extrinsic coagulation pathway
- Fibrinolysis
- Tissue/vascular repair
Describe the intrinsic and extrinsic coagulation pathway
Intrinsic: Factor XII—> Factor XI—> Factor IX—> Factor VIII— Factor X—> Factor II (thrombin)—> Factor I (fibrin)—> clot
Extrinsic: Factor III (tissue factor)—>factor VII—> Factor X—> Factor II (thrombin)—Factor I (fibrin)—> clot
What are the vitamin K dependent coagulation factors
Factor II, VII, IX, X
What is the purpose of fibrinolysis
Prevents blood clots forming pathogenic condition
What is the purpose of plasmin
Digest fibrin clots and releases fibrin degradation products and inhibits additional fibrin formation
What do FDP’s do
Inhibit thrombin and interfere with fibrin polymerization and coat platelet membranes to inhibit platelet agggregation
What is the most clinically significant and most potent coagulation inhibitor
Antithrombin III
What produces Anti-thrombin III
Hepatocytes and endothelium
What is hemorrhage
Extravasated blood caused by abnormal function or integrity of one or more of the major factors of Virchows triad
