Lecture 4 - Edema/ Cogestion/ Hemostasis Flashcards
what is the definition of edema
fluid in tissue, anasarca refers to generalized and usually severe increase in fluid
-movement of fluid across capillary walls
pathophysiology of edema: what is the effect of increased hydrostatic pressure?
impaired venous return (e.g. mechanical obstruction, congestive heart failure)
pathophysiology of edema: what is the effect of reduced plasma osmotic pressure
- reduced protein (albumin) synthesis (e.g. cirrhosis)
- increased loss of protein (e.g. nephrotic syndrome, some forms of gastroenteropathy
pathophysiology of edema: what is the effect of lymphatic obstruction
fibrosis, parasites, cancer, compression
pathophysiology of edema: what is the effect of sodium and water retention
- acute impairment of renal function
- decreased renal profusion with release of renin (e.g. congestive heart failure)
pathophysiology of edema: what is the effect of inflammation
increase vascular permeability, necrosis, angiogenesis
what are the complications of edema?
- Pulmonary edema impairs gas exchange (e.g. acute CHF)
2. Cerebral edema causes compression and herniation of critical areas, decreases blood flow
what is the definition of effusion?
collection of fluid in body cavity r or other space
- pleural, pericardial, peritoneal (ascites), joint space (synovial)
- transudate or exudate
definition of hyperemia
active vasodilation from neurogenic mechanisms or inflammation
definition of congestion
impaired venous return often accompanied by edema
examples of congestion (4 of them)
- acute pulmonary congestion (e.g. after acute myocardial infarction)
- Chronic pulmonary congestion with hemosiderin - laden macrophages (“heart failure cells”)
- Chronic hepatic congestion produced the gross appearance of “nutmeg” pattern due to blood in the centrizonal sinusoids
- Acute hepatic congestion can lead to ischemic necrosis of centrizonal hepatocytes (centrizonal necrosis)
what is the definition of hematoma
blood in tissue (literally tumor of blood)
definition of petechiae
skin or mucous membrane hemorrhages
1-2 mm in size
*petite, cute little things
definition of purpura
skin of mucous membrane hemorrhages larger than 3-9 mm
definition of ecchymoses
focal skin and subcutaneous hemorrhage, more than or equal to 1 cm
hemothorax, hemopericardium, hemarthrosis (joint), hemoperitoneum are all under the broad category of…
hemorrhage
ok i admit this was a shitty question
what are the clinical consequences of hemorrhage
- acute hemorrhage of more than 20% of blood volume leads to SHOCK
- chronic blood loss leads to iron deficiency anemia
(nooooooo not more questions about the stupid anemias)
What are the antithrombotic properties of hemostasis in reference to the endothelium
- barrier from extracellular matrix (ECM)
- prostacyclin (PGI2) inhibits platelet adhesion
anticoagulant properties - heparin like molecules allows antithrombin III (AT III) to inactivate
thrombin, Xa and other factors
anticoagulant properties - thrombomodulin bind to thrombin and this complex inactivates …
protein C
anticoagulant properties - synthesis of protein S - it is a cofactor needed for…
full protein C function, inactivation of Va and VIIIa
what physiological process is synthesis of tissue plasminogen activator (tPA) needed for
antigoagulation
what are the three phases of forming the platelet plug?
adhesion, secretion, and aggregation
what is the definition of adhesion in reference to the platelet plug?
mediated by von Willebrand factor which bridges b/w collagen and surface platelet receptor (glucoprotein Ib)
what is the definition of secretion in reference to the platelet plug?
release of contents from both types of granules
- ADP mediates platelet aggregation and calcium is required for the coagulation cascade
- there is surface expression of phospholipid complex which is a binding sire for calcium and coagulation factors
what is the definition of aggregation in reference to the platelet plug?
stimulated by ADP and thromboxane A2
- Thrombin derived from the coagulation cascade binds to a platelet surface receptor leading to more aggregation (reversible phase) and platelet contraction (irreversible phase)
- Fibrinogen binds to the platelet surface receptor GP IIb- IIIa and the platelet plug becomes cemented by fibrin
coagulation cascade is a series of enzymatic conversion of inactive ____ to activated ______
inactive proenzymes to activated enzymes
coagulation cascade - binding of calcium, active enzyme cofactor and substrate (the proenzyme) occurs at the..
phospholipid complex on platelet membranes
in the coagulation cascade the extrinsic system is activated by…
tissue factor (thromboplastin)
in the coagulation cascade the intrinsic system is activated by …
factor XII (hageman factor)
the final products of both the intrinsic and extrinsic systems are….
thrombin and fibrin
control of excess coagulation is by….
antithrombins (including (AT III) which inhibit activity of thrombin and other coagulation factors, and protein C and S which inactive factors Va and VIIIa
fibrinolysis occurs by the activation of….
plasmin from plasminogen by tissue plasminogen activator (t-PA). plasmin breaks down fibrin to form fibrin split products
