Circulatory Disturbances Flashcards
Functions of ADP in primary hemostasis
1) attracts platelets
2) exposes 2b-3a receptor complex
Functions of Thromboxane A2 in primary hemostasis?
promotes
1) platelet aggregation
2) platelet degraulation
3) vasoconstriction
Two important regulators of secondary hemostasis
Tissue factor (Factor III) Thrombin (Factor II)
Which pathway is activated by Tissue factor (Factor III)
Extrinsic
converts soluble fibrinogen into insoluble strands of fibrin
Thrombin
This substance is release from endothelial cells and catalyzes the conversion of plasminogen to plasmin
Tissue plasminogen activator (t-PA)
Also expressed on endothelial cells, this molecule is an important cofactor for active thrombin;
Thrombomodulin
Two important proteins activated by the thrombin-thrombomodulin complex
Protein C
Thrombin-activatable fibrinolysis inhibitor (TAFI)
This protein is essential for control of coagulation because it inactivates factors V and VIII
Protein C
This important molecule, activated by thrombin, down-regulates fibrinolysis by removing the binding sites on fibrin that are important for plasminogen activation
Thrombin activatable fibrinolysis inhibitor (TAFI)
3 important factors released by endothelial cells to prevent platelets from adhering when not damaged
Nitric oxide
Prostacyclin (PGI2)
Adenosin diphosphatase
This specific FDP can be used to diagnose thrombotic events and DIC
D-dimer
vWF binds to subendothelial collagen and expresses what receptor to bind platelets?
1b-9-5
The principal inhibitor of tPA and urokinase
Plasminogen activator inhibitor (PAI)
tPA & urokinase are important activators of
Plasminogen (they activate fibrinolysis)
two important platelet membrane receptors; what they bind
2b-3a–>binds fibrinogen (aggregation)
1b-9-5–>binds vWF (adhesion)
3 important contents of platelet alpha granules
Fibrinogen, fibronectin, factor V
Overall goal of the coagulation system
activate thrombin
Vitamin K dependent factors
II, VII, IX, X
Which coag factor cross-links and stablizes fibrin?
Factor XIII
Which coag pathway is able to more rapidly generate factor X
Extrinsic (tissue factor pathway)
This anti-coagulant protein reversibly inhibits the EXTRINSIC pathway
Tissue factor pathway inhibitor (TFPI)
Which pathway is needed for sustained generation of factor X; why?
Intrinsic pathway
less susceptible to inhibition
Excessive tissue factor release (i.e. lots of endothelial damage) can trigger?
Hypercoagulation and DIC
Which factors are part of the prothrombinase complex?
Factors X & V
Function of the prothrombinase complex?
catalyzes the conversion of prothrombin to thrombin
Most common coagulopathy associated with snake venom
venom-induced consumption coagulopathy (toxins activate the coag pathway)
Two common reasons for deficiency in Proteins C & S
1) acquired deficiency in horses with colic
2) DIC (dogs)
the most important serine protease inhibitor that’s activated by heparin-like molecules on endothelial cells
Antithrombin 3
The 3 things that AT3 inhibits
activity of thrombin
Factor IX
Factor X
Heparin-like molecules are expressed on _______ endothelial cells
healthy
Most common activator of plasminogen
tPA (tissue plasminogen activator)
Mutated factor V is resistant to?
actions of Protein C (means factor V can’t be turned off properly)
How can vitamin C deficiency lead to hemorrhage?
vitamin C is a cofactor for enzymes that help produce collage–>weaker capillaries
Passive process caused by reduced outflow of blood from a tissue
congestion
3 factors that play a role in thrombus formation (Virchow’s triad)
1) endothelial damage
2) alteration of normal blood flow
3) hypercoaguability
How can you differentiate a thrombus from a post-mortem clot?
post-mortem clots are NOT ADHERED to the vessel wall
3 distinguishing characteristics of arterial thrombi?
1) extend downstream from point of attachment
2) firmly attached to vessel wall
3) contain lines of zhan
3 distinguishing characteristics of venous thrombi?
1) extend upstream from point of attachment
2) loosely attached to vessel wall
3) molded to vessel lumen
Major cause of arterial thrombosis?
atherosclerosis
4 fates of a thrombus
propagation
embolization
dissolution
organization
A pulmonary thromboembolism:
1) where do they usually form
2) which lung lobes are most affected
1) in large, deep veins
2) caudal lung lobes (receive most of the R ventricle output)
where does the thrombus form in HCM?
left atria (due to stagnant blood flow)
What type of embolism is the major concern with fractured long bones?
fat embolism
In fish, an increase in the dissolved gas pressure above the ambient air pressure due to increased partial pressure of nitrogen causes
Gas bubble disease (air embolism in fish)
Venous occlusions usually cause?
Red infarcts
Arterial occlusions usually cause?
White (pale) infarcts
Name 4 diseases associated with thrombus formation
Hyperadrenocorticism
Diabetes Mellitus
Pancreatitis
Neoplasia
Thromboembolic disease associated with hyperadrencorticism is mainly caused by deficiency of?
Antithrombin (via consumption)
Fluid that passes through a NORMAL vascular wall due to imbalanced pressure forces
pure transudate (cell & protein poor)
Fluid leakage from a vessel due to increased hydrostatic pressure or increased vascular permeability
modified transudate (moderate # of cells and protein)
Define anasarca
extreme, generalized edema
What specific glomerular fenestrations help to exclude proteins?
GEnC
Which amyloidosis is most common in animals and is associated with chronic inflammation?
AA amyloidosis
Lymphangiectasis
pathologic dilation of lymphatic vessels
The physiologic response to shock is attempting to do what 2 things?
1) restore circulating volume
2) increase BP
Type of shock that’s due to myocardial failure and inability to pump blood to tissues
cardiogenic shock
Shock caused by a critical decrease in intravascular volume
hypovolemic shock
Which type of shock is not mediated by cytokine release?
neurogenic shock
Shock organ of cats?
lungs (dogs–>liver)
What can’t hypothermic cats do?
regulated BP
