edema/congestion Flashcards
5 causes of edema
- increased hydrostatic pressure
- reduced plasma osmotic pressure
- lymphatic obstruction
- sodium and water retention
- inflammation
increased hydrostatic pressure can result from _____
impaired venous return (i.e. mechanical obstruction, CHF)
reduced plasma osmotic pressure can result from _____ or _____
- reduced protein (albumin) synthesis (i.e. cirrhosis)
- increased loss of protein (i.e. nephrotic syndrome, some forms of gastroenteropathy)
pulmonary edema impairs _____ (e.g. acute congestive heart failure)
gas exchange
cerebral edema causes _____ and ____ of critical areas which decreases _____
compression; herniation; blood flow
collection of fluid in body cavity or other space
effusion (transudate or exudate)
local increase in intravascular blood volume (increased tissue blood volume)
hyperemia/congestion
hyperemia is increased tissue blood volume secondary to _____ or _____; is considered ____
neurogenic mechanisms; inflammation
hyperemia = active vasodilation
congestion is increased tissue blood volume secondary to ______
impaired venous return (passive)
4 examples of congestion
- acute pulmonary congestion (after acute MI)
- chronic pulmonary congestion
- chronic hepatic congestion
- acute hepatic congestion
chronic hepatic congestion produces gross appearance of _____ due to blood in the _____
nutmeg pattern; centrizonal sinusoids
acute hepatic congestion can lead to ______ of _____
ischemic necrosis ; centrizonal hepatocytes (centrizonal necrosis)
loss of blood secondary to vessel injury or physical disruption
hemorrhage
types of internal hemorrhages
- hematoma
- petechiae
- purpura
- ecchymoses (bruise)
- hemothorax, hemopericardium, hemarthrosis (joint), hemoperitoneum (hemorrhage into body spaces)
hematoma is blood in ____
tissue (literally tumor of blood)
petechiae are ____ or ____ hemorrhages ____ in size ; can be seen in mono
skin; mucous membrane; 1-2 mm
purpura are ___ or ____ hemorrhages larger than ____ in size
skin; mucous membrane; 3-9 mm
ecchymoses (bruise) is a focal ____ and ____ hemorrhage
skin; subcutaneous (greater than or equal to 1 cm)
acute hemorrhage of > 20% of blood volume leads to ____
shock
chronic blood loss leads to _____
iron deficiency anemia
rapid arrest of blood loss at site of injury
hemostasis
3 major components of hemostasis
- endothelium
- platelets
- coagulation cascade
antithrombotic properties of the endothelium act as a barrier from the _____; _____ inhibits platelet aggregation
extracellular matrix (ECM); prostacyclin (PGI2)
_____ allow anti-thrombin III (AT-III) to inactivate ____, ___, and other factors
heparin-like molecules; thrombin; Xa
____ binds to thrombin and this complex activates ____, an anticoagulent
thrombomodulin; protein C
protein C inhibits clotting by cleaving and inactivating two procoagulents, factors ___ and ___ ; protein C needs a cofactor, _____, synthesized by endothelial cells
Va; VIIIa; protein S
endothelial cells synthesize _____, a protease that cleaves ____ to ____
tissue plasminogen activator (tPA); plasminogen; plasmin (plasmin in turn cleaves fibrin to degrade thrombi)
3 prothrombotic properties of endothelium
- von Willebrand factor
- tissue factor
- inhibitors of plasminogen activity
vWF is a cofactor for binding ____ to ____
platelets; collagen
tissue factor (major in vivo regulator of _____) is secreted after exposure to _____ (referred to as endothelial activation) and initiates the ______
coagulation; cytokines; extrinsic clotting pathway
inhibitors of plasminogen activity limit ____ and thereby favor ____
fibrinolysis (enzymatic breakdown of fibrin in blood clots); thrombosis
3 phases to forming the platelet plug
- adhesion
- secretion
- aggregation
after vascular injury, platelets encounter _____ and ____
ECM constituents (collagen most important); adhesive glycoproteins (such as vWF)
adhesion is mediated by ____ which bridges between collagen and a surface platelet receptor (gp lb)
vWF
____ mediates platelet aggregation and ____ is required for the coagulation cascade
ADP; calcium
aggregation is stimulated by ____ and ____
ADP; thromboxane A2
____ derived from the coagulation cascade binds to a platelet surface receptor leading to more _____ (reversible) and ____ (irreversible)
aggregation; platelet contraction
____ binds to the platelet surface receptor GP IIb-IIIa and the platelet plug becomes cemented by ____
fibrinogen; fibrin
extrinsic system activated by _____
tissue factor (thromboplastin)
intrinsic system activated by _____
factor XII (hageman factor)
final products of both systems are ___ and ____
thrombin and fibrin
control of excess coagulation is by _____ which inhibit activity of thrombin and other coagulation factors, and ____ which inactivate _____
antithrombins (AT-III); proteins C and S; factors Va and VIIIa
fibrinolysis occurs through activation of ____ from ____ by _____
plasmin; plasminogen; tissue plasminogen activator (tPA)
plasmin breaks down ____, resulting in _____
fibrin; fibrin split/degradation products
