L18: Peturbations of Flow 2 (Thrombosis) Flashcards
What are the three major mechanisms predisposing animals to thrombosis?
Endothelial cell injury Abnormal haemodynamics (stasis, turbulence) Hypercoagulability
How does blood turbulence predispose to thrombosis?
damage to EC and local stasis, accelerates intravascular procoagulant factors
How does blood stasis predispose to thrombosis
hypercoaulability due to increase pooling/ contact, hypoxic injury to EC
Which circumstances lead to blood hypercoagulability
preg, DIC, snakebite, pancreatic necrosis, severe tissue trauma
Describe basic events of thrombus formation
EC trauma so adopt procuagulant phenotype/ “activated” > release EDP, thromboxane etc. for recruitment > cascade results in conversion of insoluble fibrinogen into fibrin
Whats a mural thrombus?
partially protruding into lumen, not totally occlusive
lines of Zahn are what
microscopic lamination
Gross appearance of thrombus in artery or heart?
firm, pale yellow, dry, rough chiefly platelets, fibrin High velocity so pressure sweeps RBC away prominent laminations slow propagation firm anchorage
Gross appearance of thrombus in vein?
moist, dark red, generally occlusive, larger, attachment points fragile, longer tail
What gross features would allow you to distinguish between an ante mortem venous thrombus and a post mortem red currant blood clot?
Not attached to vessel wall, gelatinous, red and white separated
Ante mortem are attached (fine tangled strands fibrin) and congestion and oedema upstream
Are venous or arterial thrombi more likely to embolise?
venous mate
How do thrombi undergo organisation? What is meant by the term recanalisation of a thrombus?
Phagocytosis by leukocytes, ingrowth EC, SMC, fibroplasts
Capillaries anastomose to allow longitudinal recanalisation
